Tuesday, April 30, 2013

Simple Thermal Fan Controller By IC 741

The controller uses one or more ordinary silicon diodes as a sensor, and uses a cheap opamp as the amplifier. I designed this circuit to use 12V computer fans, as these are now very easy to get cheaply. These fans typically draw about 200mA when running, so a small power transistor will be fine as the switch. I used a BD140 (1A, 6.5W), but almost anything you have to hand will work just as well.

Circuit diagram:Thermal Fan Controller by IC 741 and Diode
Thermal Fan Controller Circuit Diagram
Source: ESP
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Sunday, April 21, 2013

Audio Booster Circuit

Small and portable unit, Can be built on a veroboard
The amplifiers gain is nominally 20 dB. Its frequency response is determined primarily by the value of just a few components-primarily C1 and R1. The values of the schematic diagram provide a response of ±3.0 dB from about 120 Hz to better than 20,000 Hz.Actually, the frequency response is ruler flat from about 170 Hz to well over 20,000 Hz; its the low end that deviates from a flat frequency response. 

The low ends roll-off is primarily a function of capacitor C1(since RIs resistive value is fixed). If C1s value is changed to 0.1 pF, the low ends comer frequency-the frequency at which the low-end roll-off starts-is reduced to about 70 Hz. If you need an even deeper low-end roll-off, change C1 to a 1.0 pF capacitor; if its an electrolytic type, make certain that its installed into the circuit with the correct polarity, with the positive terminal connected to Q1s base terminal.

Circuit Diagram:
Audio_Booster_Circuit Diagram Audio Booster Circuit Diagram

Parts Description
P1 100K
R1 47K
R2 470K
R3 10K
R4 560R
R5 270R
C1 0.1uF-25v
C2 3.3uF-25v
C3 470uF-25V
D1 5mm. Red Led
B1 9v Battery
J1 RCA Audio Input Socket
J2 RCA Audio Output Socket
S1 On-Off Switch

Source :http://www.ecircuitslab.com
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Saturday, April 13, 2013

Power Supply Failure Alarm

Most of the power supply failure indicator circuits need a separate power-supply for them-selves. But the alarm circuit presented here needs no additional supply source. It employs an electrolytic capacitor to store adequate charge, to feed power to the alarm circuit which sounds an alarm for a reasonable duration when the mains supply fails. During the presence of mains power supply, the rectified mains voltage is stepped down to a required low level.

Power Supply Failure Alarm Circuit Diagram

Power-Supply-Failure-Alarm Circuit Diagram

A zener is used to limit the filtered voltage to 15-volt level. Mains presence is indicated by an LED. The low-level DC is used for charging capacitor C3 and reverse biasing switching transistor T1. Thus, transistor T1 remains cut-off as long as the mains supply is present. As soon as the mains power fails, the charge stored in the capacitor acts as a power-supply source for transistor T1. Since, in the absence of mains supply, the base of transistor is pulled ‘low’ via resistor R8, it conducts and sounds the buzzer (alarm) to give a warning of the power-failure.

With the value of C3 as shown, a good-quality buzzer would sound for about a minute. By increasing or decreasing the value of capacitor C3, this time can be altered to serve one’s need. Assembly is quite easy. The values of the components are not critical. If the alarm circuit is powered from any external DC power-supply source, the mains supply section up to points ‘P’ and ‘M’can be omitted from the circuit.

Following points may be noted:
1. At a higher  DC voltage level, transistor T1 (BC558) may pass some collector-to-emitter leakage current, causing a continuous murmuring sound from the buzzer. In that case, replace it with some low-gain transistor.
2. Piezo buzzer must be a continuous tone version, with built-in oscillator. To save space, one may use five small-sized 1000µF capacitors (in parallel) in place of bulky high-value capacitor C3.

Source :http://www.ecircuitslab.com/2011/11/power-supply-failure-alarm.html

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Variable DC Power Supply Circuit Diagram

Voltage Range: 0.7V to 24V, Current Range: 50mA to 2A

A variable dc power supply is one of the most useful tools on the electronics hobbyists workbench. This circuit is not an absolute novelty, but it is simple, reliable, "rugged" and short-proof, featuring variable voltage up to 24V and variable current limiting up to 2A. You can adapt it to your own requirements as explained in the notes below.

Circuit Diagram :

Variable DC Power Supply Circuit Diagram

Variable DC Power Supply Circuit Diagram


P1 = 500R
P2 = 10K
R1 = 2.2K-1/2w
R2 = 2.2K-1/2w
R3 = 330R
R4 = 150R
R5 = 1R-5W
C1 = 35V-3300uF
D1 = 1N5402
D2 = 1N5402
D3 = 5mm Red Led
C2 = 63V-1uF
Q1 = BC182
Q2 = BD139
Q3 = BC212
Q4 = 2N3055
SW1 = SPST Mains Switch
T1 = 36VCT-Transformer


  • P1 sets the maximum output current you want to be delivered by the power supply at a given output voltage.
  • P2 sets the output voltage and must be a logarithmic taper type, in order to obtain a more linear scale voltage indication.
  • You can choose the Transformer on the grounds of maximum voltage and current output needed. Best choices are: 36, 40 or 48V center-tapped and 50, 75, 80 or 100VA.
  • Capacitor C1 can be 2200 to 6800µF, 35 to 50V.
  • Q4 must be mounted on a good heatsink in order to withstand sustained output short-circuit. In some cases the rear panel of the metal box in which you will enclose the circuit can do the job.
  • The 2N3055 transistor (Q4) can be replaced with TIP3055 type.

Source : www.redcircuits.com

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Class A Headphone Amplifier

This circuit is derived from the Portable Headphone Amplifier featuring an NPN/PNP compound pair emitter follower output stage. An enhanced output using capability is acquireed by way of making this a push-pull Class-A arrangement. Output energy can reach 427mW RMS into a 32 Ohm load at a fixed standing present of 100mA. The single voltage acquire stage permits the straightforward implementation of a shunt-feedback circuitry giving superb frequency stability.
Circuit diagram :

Class-A Headphone Amplifier Circuit diagram

The above mentioned shunt-feedback configuration also allows the simple addition of frequency established networks to be in a position to acquire an useful, unobtrusive, switchable Tilt keep an eye fixed on (optional). When SW1 is ready within the first position a gentle, shelving bass elevate and treble lower is get preserve ofed. The valuable place of SW1 allows a flat frequency response, whereas the 1 of 3 place of this switch permits a shelving treble raise and bass reduce.
  • Before surroundings quiescent current rotate the volume control P1 to the minimum, Trimmer R6 to zero resistance and Trimmer R3 to concerning the center of its travel.
  • Connect a suitable headphone set or, higher, a three3 Ohm 1/2W resistor to the amplifier output.
  • Connect a Multimeter, set to measure about 10Vdc fsd, throughout the positive end of C5 and the poor floor.
  • Switch on the availability and rotate R3 so as to examine 7.7-7.8V on the Multimeter show.
  • Switch off the availability, disconnect the Multimeter and reconnect it, set to measure at the least 200mA fsd, in series to the positive provide of the amplifier.
  • Switch on the provide and rotate R6 slowly except a studying of about 100mA is displayed.
  • Check again the voltage on the certain end of C5 and readjust R3 if important.
  • Wait about quarter-hour, watch if the present is varying and readjust if essential.
Parts List :
P1          : 22K  Dual gang Log Potentiometer 
R1 : 15K
R2 : 220K
R3 : 100K
R4 : three3K
R5 : 68K
R6 : 50K
R7 : 10K
R8,R9 : four7K
R10,R11 : 2R2
R12 : fourK7
R13 : fourR7
R14 : 1K2
R15,R18 : 330K
R16 : 680K
R17,R19 : 220K
R20,R21 : 22K
C1,C2,C3,C4 : 10µF/25V
C5,C7 : 220µF/25V
C6,C11 : 100nF
C8 : 2200µF/25V
C9,C12 : 1nF
C10 : 470pF
C13 : 15nF
D1 : LED
D2,D3 : 1N4002
Q1,Q2 : BC550C
Q3 : BC560C
Q4 : BD136
Q5 : BD135
IC1 : 7815
T1 : 15CT/5VA Mains transformer
SW1 : four poles 3 manners rotary Switch
SW2 : SPST slide or toggle Switch
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Low drop Regulator with Indicator

Even today much logic is still powered from 5 volts and it then seems obvious to power the circuit using a standard regulator from a rectangular 9-V battery. A disadvantage of this approach is that the capacity of a 9-V battery is rather low and the price is rather high. Even the NiMH revolution, which has resulted in considerably higher capacities of (pen-light) batteries, seems to have escaped the 9-V battery generation. It would be cheaper if 5 volts could be derived from 6 volts, for example. That would be 4 ‘normal’ cells or 5 NiMH- cells. Also the ‘old fashioned’ sealed lead- acid battery would be appropriate, or two lithium cells.
Circuit diagram : 
Low-drop Regulator with Indicator-Circuit-Diagram
Low-drop Regulator with Indicator Circuit Diagram
Using an LP2951, such a power supply is easily realised. The LP2951 is an ever- green from National Semiconductor, which you will have encountered in numerous  Elektor Electronics designs already. This IC can deliver a maximum current of 100 mA at an input voltage of greater than 5.4 V. In addition to this particular version, there are also versions available for 3.3 and 3 V output, as well as an adjustable version.  In this design we have added a battery indicator, which also protects the battery from too deep a discharge. As soon as the IC has a problem with too low an input voltage, the ERROR output will go low and the regulator is turned off via IC2d, until a manual restart is provided with the RESET pushbutton.
The battery voltage is divided with a few resistors and compared with the reference voltage (1.23 V) of the regulator IC. To adapt the indicator for different voltages you only need to change the 100-k resistor. The comparator is an LP339. This is an energy-friendly version of the LM339. The LP339 consumes only 60 µA and can sink 30 mA at its output. You can also use the LM339, if you happen to have one around, but the current consumption in that case is 14 times higher (which, for that matter, is still less than 1 mA).
Finally, the LP2951 in the idle state, consumes about 100 µA and depend- ing on the output current to be deliv- ered, a little more. 

Source by : Streampowers
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Remote Control Blocker

This circuit was once designed to dam signals from infrared far off controls. This will prove very helpful if your children have the tendency to change channels all the time. It is also effective when your kids aren’t accepted to seem to be at TV as a punishment. Putting the TV on standby and put-ting the faraway keep a watch on out of motion can additionally be sufficient in this case. 

Circuit diagram :

Remote Control Blocker Circuit Diagram

The manner in which we do that is very easy. Two IR LEDs constantly transmit infrared gentle with a frequency that may be set between 32 and 41 kHz. Most far off controls work at a frequency of 36 kHz or 38 kHz. 

The disruption of the remote keep watch over occurs as follows. The ‘automatic gain’ of the IR receiver in TVs, CD avid gamers, home cinema techniques, and many others. reduces the gain of the receiver because of the strong signal from the IR LEDs. Any IR indicators from a far off regulate are then too vulnerable to be detected by the receiver. Hence the equipment not ‘sees’ the remote control! 
The oscillator is constructed round a typical NE555. This powers a buffer stage, which gives the present to the 2 LEDs. Setting up this circuit is very easy. Point the IR LEDs against the tool that wants its far flung control blocked. Then pick up the far flung keep watch over and take a look at it out. If it still functions you should alter the frequency of the circuit unless the far flung keep watch over stops working.
This circuit is obviously simplest efficient against remote keep watch overs that use IR gentle!

Author : Paul Goossens - Copyright : Elektor
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Friday, April 12, 2013

Little Door Guard

If some intruder tries to open the door of your house, this circuit sounds an alarm to provide you with a warning once morest the tried intrusion. The circuit (Fig. 1) makes use of easily on hand, low-priced components. For compactness, an alkaline 12V battery is used for energying the unit. Input DC supply is further regulated to a gentle DC voltage of 5V with the aid of 3-pin regulator IC 7805 (IC2).

Fig. 1: Circuit of the door guard

Assemble the unit on a general-purpose PCB as proven in Fig. four and mount the identical on the door as shown in Fig. three. Now mount a section of reflect on the door body such that it is precisely aligned with the unit. Pin configurations of IC UM3561 and transistors 2N5777 and BC547 are shown in Fig. 2. 

Fig. 2: Pin configurations of UM3561 and transistors 2N5777 and BC547

Initially, when the door is closed, the infrared (IR) beam transmitted by means of IR LED1 is reflected (by the reflect) again to phototransistor 2N5777 (T1). The IR beam falling on phototransistor T1 reverse biases npn transistor T2 and IC1 does not get sure provide at its pin 5. As a outcome, no tone is produced at its output pin 3 and the loudspeaker continues to be silent. Resistor R1 limits the operating present for the IR LED.
When the door isopened, the absence of IR rays at phototransistor T1 ahead biases npn transistor T2, which provides provide to  positiveIC1. Now three-sirensound generator IC UM3561 (IC1) will get power via resistor R5. The output of IC1 at pin 3 is amplified by using Darlington-pair transistors T3 and T4 to produce the alert tone by means of the loudspeaker. 

Fig. 3: Back view of the door assembly

Rotary change S2 is used to make a choice the three preprogrammed tones of IC1. IC1 produces fireplace engine, police and ambulance siren sounds when its pin 6 is connected to point F, P or A, respectively.

Fig. 4: Suggested enclosure with major elements layout

Author : T.K. Hareendran - Copyright : EFY
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Simple Solar Flasher

This Simple Solar Flasher circuit is a single transistor fly back (Joule Thief) circuit that features a third coil. With it, flash duration and brightness is much enhanced, without resorting to large value capacitors.

Circuit Diagram:

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Simplest Efficient 1 Watt LED Driver Circuit

1 Watt Simple LED Driver Circuit with Current Control, Circuit Diagram,

As can be seen in the diagram, the concept hardly utilizes any circuit or rather does not incorporate any hi-end active component for the required implementation of driving a 1 watt LED.

The only active devices thats been employed in the circuit are a few diodes and a mechanical switch.

The initial 6 volts from a charged battery is dropped to the required 3.5 volts limit by keeping all the diodes in series or in the path of the LED supply voltage.

Since each diode drops 0.6 volts across it, all four together allow only 3.5 volts to reach the LED, lighting it safely, yet brightly.

As the illumination of the LED drops, each diode is bypassed subsequently using the switch, to restore the brightness of the LED.

The use of the diodes for dropping the voltage level across the LEDs makes sure that the procedure does not dissipate any heat and therefore becomes very efficient in comparison to a resistor, which would have otherwise dissipated a lot of heat in the process.

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Converting a DCM Motor

We recently bought a train set made by a renowned company and just couldn’t resist looking inside the locomotive. Although it did have an electronic decoder, the DCM motor was already available 35 (!) years ago. It is most likely that this motor is used due to financial constraints, because Märklin (as you probably guessed) also has a modern 5-pole motor as part of its range. Incidentally, they have recently introduced a brushless model. 

The DCM motor used in our locomotive is still an old-fashioned 3-pole series motor with an electromagnet to provide motive power. The new 5-pole motor has a permanent magnet. We therefore wondered if we couldn’t improve the driving characteristics if we powered the field winding separately, using a bridge rectifier and a 27 Ω current limiting resistor. This would effectively create a permanent magnet. The result was that the driving characteristics improved at lower speeds, but the initial acceleration remained the same. But a constant 0.5 A flows through the winding, which seems wasteful of the (limited) track power. A small circuit can reduce this current to less than half, making this technique more acceptable. 

Circuit diagram :
Converting a DCM Motor-Circuit Diagram
Converting a DCM Motor Circuit Diagram

The field winding has to be disconnected from the rest (3 wires). A freewheeling diode (D1, Schottky) is then connected across the whole winding. The centre tap of the winding is no longer used. When FET T1 turns on, the current through the winding increases from zero until it reaches about 0.5 A. At this current the voltage drop across R4-R7 becomes greater than the reference voltage across D2 and the opamp will turn off the FET. The current through the winding continues flowing via D1, gradually reducing in strength. When the current has fallen about 10% (due to hysteresis caused by R3), IC1 will turn on T1 again. The cur-rent will increase again to 0.5 A and the FET is turned off again. This goes on continuously.
The current through the field winding is fairly constant, creating a good imitation of a permanent magnet. The nice thing about this circuit is that the total current consumption is only about 0.2 A, whereas the current flow through the winding is a continuous 0.5 A. 

We made this modification because we wanted to convert the locomotive for use with a DCC decoder. A new controller is needed in any case, because the polarity on the rotor winding has to be reversed to change its direction of rotation. In the original motor this was done by using the other half of the winding.
There is also a good non-electrical alter-native: put a permanent magnet in the motor. But we didn’t have a suitable magnet, whereas all electronic parts could be picked straight from the spares box. 

Source By : Streampowers
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PIC Controlled Relay Driver

This circuit is a relay driver that is based on a PIC16F84A microcontroller. The board includes four relays so this lets us to control four distinct electrical devices. The controlled device may be a heater, a lamp, a computer or a motor. To use this board in the industrial area, the supply part is designed more attentively. To minimize the effects of the ac line noises, a 1:1 line filter transformer is used.

PIC-Controlled-Relay Driver Final
The transformer is a 220V to 12V, 50Hz and 3.6VA PCB type transformer. The model seen in the photo is HRDiemen E3814056. Since it is encapsulated, the transformer is isolated from the external effects. A 250V 400mA glass fuse is used to protect the circuit from damage due to excessive current. A high power device which is connected to the same line may form unwanted high amplitude signals while turning on and off. To bypass this signal effects, a variable resistor (varistor) which has a 20mm diameter is paralelly connected to the input.
 Controller-Schematic Circuit

Another protective component on the AC line is the line filter. It minimizes the noise of the line too. The connection type determines the common or differential mode filtering. The last components in the filtering part are the unpolarized 100nF 630V capacitors. When the frequency increases, the capacitive reactance (Xc) of the capacitor decreases so it has a important role in reducing the high frequency noise effects. To increase the performance, one is connected to the input and the other one is connected to the output of the filtering part.

Supply-Schematic circuit

After the filtering part, a 1A bridge diode is connected to make a full wave rectification. A 2200 uF capacitor then stabilizes the rectified signal. The PIC controller schematic is given in the project file. It contains PIC16F84A microcontroller, NPN transistors, and SPDT type relays. When a relay is energised, it draws about 40mA. As it is seen on the schematic, the relays are connected to the RB0-RB3 pins of the PIC via BC141 transistors. When the transistor gets cut off, a reverse EMF may occur and the transistor may be defected. To overcome this unwanted situation, 1N4007 diodes are connected between the supply and the transistor collectors. There are a few number of resistors in the circuit. They are all radially mounted. Example C and HEX code files are included in the project file. It energizes the next relay after every five seconds.

The components are listed below.
1 x PIC16F84A Microcontroller
1 x 220V/12V 3.6VA (or 3.2VA) PCB Type Transformer (EI 38/13.6)
1 x Line Filter (2x10mH 1:1 Transformer)
4 x 12V Relay (SPDT Type)
4 x BC141 NPN Transistor
5 x 2 Terminal PCB Terminal Block
4 x 1N4007 Diode
1 x 250V Varistor (20mm Diameter)
1 x PCB Fuse Holder
1 x 400mA Fuse
2 x 100nF/630V Unpolarized Capacitor
1 x 220uF/25V Electrolytic Capacitor
1 x 47uF/16V Electrolytic Capacitor
1 x 10uF/16V Electrolytic Capacitor
2 x 330nF/63V Unpolarized Capacitor
1 x 100nF/63V Unpolarized Capacitor
1 x 4MHz Crystal Oscillator
2 x 22pF Capacitor
1 x 18 Pin 2 Way IC Socket
4 x 820 Ohm 1/4W Resistor
1 x 1K 1/4W Resistor
1 x 4.7K 1/4W Resistor
1 x 7805 Voltage Regulator (TO220)
1 x 7812 Voltage Regulator (TO220)
1 x 1A Bridge Diode

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Simple Water Sensor Circuit Diagram using IC 555

This is a water sensor /rain alarm circuit diagram; it can be used on motorcycle, car or other device that we want to protect from water, rain. This is a simple water sensor/rain alarm circuit that makes an alarm when water/rain falls on its sensor. This circuit is based on NE555/LM555 IC and two transistors (Q1&Q2). For transistor Q1- BC547 or BC107 and for Q2- 2N825,BC548 or BC168 can be used in the circuit. 

This rain detector circuit can be supplied from voltage source of +9V-12V DC. The resistor 470K ohm is a POT/Variable resistor; it is used to adjust the sensitivity of water/rain sensor. Use a 8 ohm,0.5w-1W speaker to hearing better alarm. Less than 8 ohm speaker could be harmful for the IC 555. 

Circuit Diagram of Water Sensor 
Simple Water Sensor Circuit Diagram using IC 555

 We can make the water sensor as shown in the image (Fig-1) using aluminum conductor like a naked wire . Here can be used other conductor but we suggesting to use aluminum.
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1995 Ford Windstar Wiring Diagram

1995 Ford Windstar Wiring Diagram

The Part of 1995 Ford Windstar Wiring Diagram: starting system, battery, fusible link, instrument cluster,
fuse panel, ignition switch, digital cluster, analog cluster, integral alternator regulator, screw, field, warning indicator, stator, rectifier, switching circuits
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Introduction to Amplifier Rise

Amplification is the method of increasing the amplitude of a AC sign present or voltage this type ofs audio signal for sound or video signal for a tv picture. The amplifier permits a small input sign to keep watch over a so much bigger amount of energy in the output circuit. The output sign is a reproduction of the original enter sign however has larger amplitude.

Amplification is important as in most softwares, the sign is weak for use straight away. For instance, an audio output of 1mV from a microphone is unable to pressure a loud speaker which requires a quantity of volts to operate. Hence, the signal require to be amplified to some volts prior to it may also be fed in to the loud speaker.

NP N Transistor Circuit Configurations
An instance of various type of transistor configurations in the circuit is as shown in Figure one beneath.

(1) The well-liked emitter(CE) circuit makes use of emitter as its common electrode. The input signal is utilized to the bottom and the amplified output is taken from the collector. This is the on a standard basis use as a result of its one of the best aggregate of present achieve & voltage acquire.

(2) The standard base (CB) circuit makes use of base as its standard electrode. The enter signal is utilized to the emitter & the amplified output is taken from the collector. The comparatively excessive emitter current in comparability with the base current ends in low input impedance worth. For this motive, the CB circuit isn't used.

(3) The fashionable collector (CC) circuit makes use of collector as its widespread electrode. The input signal is applied to the base & the amplified output is taken from the emitter. This circuit is also known as an emitter practiceer. This name means that the output sign voltage on the emitter follows the enter signal at the base with the same segment however less amplitude. The voltage acquire is not up to one & is on an ordinary basis used for impedance matching. Its excessive input on the base as a load for the earlier circuit & low output impedance on the emitter as a signal source for the next circuit.


They can be categoryified in to lessons A, B, C & AB. They are outlined based on the % of the cycle of enter signal that can produce output current.

In Class A, the output present go with the flows for the full cycle of 360 degree of enter signal. The distortion is the bottom with around 5% to 10% &an efficiency of 20% to 40%. In common, most tiny sign function class A

In Class C, the output current glides for lower than half of the input cycle. Typical operation is 120 degree of enter current in the coursework of the certain half of cycle of the enter present. This type has an effectivity of 80% but has the best distortion. This class is usually used for RF amplification with a tuned circuit within the output.

In Class B, the output present drifts for half of of the enter cycle which is round one hundred eighty stage. Class B operation lies between classification A & category C. Classes B are frequently related in pairs & in this kind of circuit called push-pull amplifier. The push pull is often used for audio power output to a loud speaker.

In Class AB, it provides a compromise between the low distortion of category A & the higher energy of sophistication B. It is usually used for push pull audio energy amplifiers.
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Thursday, April 11, 2013

Hard Disk Selector

In the last few years, the available range of operating systems for PCs has increased dramatically. Various free (!) operating systems have been added to the list, such as BeOS, OpenBSD and Linux. These systems are also available in different colours and flavours (versions and distributions). Windows is also no longer simply Windows, because there are now several different versions (Windows 95, 98, ME, NT, XP, Vista and 7). Computer users thus have a large variety of options with regard to the operating system to be used. One problem is that not all hardware works equally well under the various operating systems, and with regard to software, compatibility is far from being universal. In other words, it’s difficult to make a good choice.

Switching from one operating system to another - that’s a risky business, isn’t it? Although this may be a bit of an exaggeration, the safest approach is still to install two different operating systems on the same PC, so you can always easily use the ‘old’ operating system if the new one fails to meet your needs (or suit your taste). A software solution is often used for such a ‘dual system’. A program called a ‘boot manager’ can be used to allow the user to choose, during the start-up process, which hard disk will be used for starting up the computer. Unfortunately, this does not always work flawlessly, and in most cases this boot manager is replaced by the standard boot loader of the operating system when a new operating system is installed.

In many cases, the only remedy is to reinstall the software. The solution presented here does not suffer from this problem. It is a hardware solution that causes the primary and secondary hard disk drives to ‘swap places’ when the computer is started up, if so desired. From the perspective of the computer (and the software running on the computer), it appears as though these two hard disks have actually changed places. This trick is made possible by a feature of the IDE specification called ‘CableSelect’. Every IDE hard disk can be configured to use either Master/Slave or CableSelect. In the latter case, a signal on the IDE cable tells the hard disk whether it is to act as the master or slave device. For this reason, in every IDE cable one lead is interrupted between the connectors for the two disk drives, or the relevant pin is omitted from the connector.

This causes a low level to be present on the CS pin of one of the drives and a high level to be present on the CS pin of the other one (at the far end of the cable). The circuit shown here is connected to the IDE bus of the motherboard via connector K1. Most of the signals are fed directly from K1 to the other connectors (K2 and K3). An IDE hard disk is connected to K2, and a second one is connected to K3. When the computer is switched on or reset, a pulse will appear on the RESET line of the IDE interface. This pulse clocks flip-flop IC1a, and depending on the state of switch S1, the Q output will go either high or low. The state on the Q output is naturally always the opposite of that on the Q output. If we assume that the switch is closed during start-up, a low level will be present on D input of IC1a, so the Q output will be low following the reset pulse.

This low level on the Q output will cause transistor T1 to conduct. The current flowing through T1 will cause LED D1 to light up and transistor T2 to conduct. The hard disk attached to connector K2 will thus see a low level on its CS pin, which will cause it to act as the master drive and thus appear to the computer as the C: drive. A high level will appear on the Q output following the reset pulse. This will prevent T3 and T4 from conducting, with the consequence that LED D2 will be extinguished and the hard disk attached to connector K3 will see a high level on its CS pin. For this disk, this indicates that it is to act as a slave drive (D: drive).

If S1 is open when the reset pulse occurs, the above situation is of course reversed, and the hard disk attached to connector K2 will act as the D: drive, while the hard disk attached to connector K3 will act as the C: drive. Flip-flop IC1a is included here to prevent the hard disks from swapping roles during use. This could have disastrous consequences for the data on the hard disks, and it would most likely cause the computer to crash. This means that you do not have to worry about affecting the operation of the computer if you change the switch setting while the computer is running. The state of the flip-flop, and thus the configuration of the hard disks, can only be changed during a reset.

The circuit is powered from a power connector for a 3.5-inch drive. This advantage of using this connector is that it easily fits onto a standard 4-way header. However, you must observe the correct polarity when attaching the connector. The red lead must be connected to pin 1. Constructing the hard disk selector is easy if the illustrated printed circuit board is used. You will need three IDE cables to connect the circuit. The best idea is to use short cables with only two connectors, with all pins connected 1:1 (no interruption in the CS line). The IDE connector on the motherboard is connected to K1 using one cable. A cable then runs from K2 to first hard disk, and another cable runs from K3 to the second hard disk. This means that it is not possible to connect more than two hard disks to this circuit. You must also ensure that the jumpers of both disk drives are configured for CableSelect. To find out how to do this, refer to the user manual(s) for the drives
Source by : Streampowers
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12 V Glow Plug Converter

Most small internal-combustion engines commonly used in the model-building world use glow plugs for starting. Unfortunately, glow plugs have an operating voltage of 1.5 V, while fuel pumps, starter motors, chargers and the like generally run on 12 V. This means that a separate battery is always needed to power the glow plug. The standard solution is to use an additional 2-V lead storage battery, with a power diode in series to reduce the voltage by approximately 0.5 V. However, this has the annoying consequence that more than 30 percent of the energy is dissipated in the diode. Naturally, this is far from being efficient. 

Circuit diagram :
12-V Glow Plug Converter-Circuit Diagram
12-V Glow Plug Converter Circuit Diagram
The converter presented here allows glow plugs to be powered from the 12-V storage battery that is usually used for fuelling, charging, starting and so on. A car battery can also be used as a power source. Furthermore, this circuit is con-siderably more efficient than the approach of using a 2-V battery with a series power diode. 

The heart of the DC/DC converter is IC1, a MAX 1627. The converter works according to the well-known step-down principle, using a coil and an electrolytic capacitor. Here the switching stage is not integrated into the IC, so we are free to select a FET according to the desired current level. In this case, we have selected a 2SJ349 (T1), but any other type of logic-level FET with a low value of RDSonwould also be satisfactory. Of course, the FET must be able to handle the required high currents. 

Diode D1 is a fast Schottky diode, which must be rated to handle the charging currents for C2 and C3. This diode must also be a fairly hefty type. The internal resistances of coil L1 and capacitors C2 and C3 must be as low as possible. This ensures efficient conversion and prevents the components from becoming too warm.
The resistor network R2/R3 causes 87 percent of the output voltage to be applied to the FB pin of IC1. This means that an output voltage of 1.5 V will cause a voltage of approximately 1.3 V to be present at the FB pin. The IC always tries to drive the switching stage such that it ‘sees’ a voltage of 1.3 V on the FB input. If desired, a different output voltage can be provided by modifying the values of R2 and R3. 

When assembling the circuit, ensure that C5 and C1 are placed as close as possible to IC1, and use sufficiently heavy wiring between the 12-V input and the 1-5-V output, since large cur-rents flow in this part of the circuit. A glow plug can easily draw around 5 A, and the charging current flowing through the coil and into C2 and C3 is a lot higher than this!
Source by : streampowers
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Video Amplifier Circuit Diagram

The video amplifier in the diagram is a well-known design. Simple, yet very useful, were it not for the ease with which the transistors can be damaged if the potentiometers (black level and signal amplitude) are in their extreme position. Fortunately, this can be obviated by the addition of two resistors. If in the diagram R3 and R4 were direct connections, as in the original design, and P1 were fully clockwise and P2 fully anticlockwise, such a large base current would flow through T1 that this transistor would give up the ghost.

Circuit diagram:


Video Amplifier Circuit Diagram

Moreover, with the wiper of P2 at earth level, the base current of T2 would be dangerously high. Resistors R3 and R4 are sufficient protection against such mishaps, since they limit the base currents to a level of not more than 5 mA. Shunt capacitor C4 prevents R4 having an adverse effect on the amplification.

Author: L.A.M. Prins - Copyright: Elektor Electronics

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Paraphase Tone Controller

As opposed to the widespread Baxandall circuit (dating back to 1952!) a ‘paraphrase’ tone control supplies a straight frequency response as long as the bass and treble controls are in the same position. This unique property makes the ‘paraphase’ configuration of interest if only treble or bass needs to be adjusted - it is not possible to adjust both at the same time! Essentially, it’s the difference in setting of the tone controls that determines the slope of the frequency response, and the degree of bass/treble correction. The circuit is simplicity itself, based on two networks C1-C2-C3/R9-R10-R11 and C5-C6-C7/R12-R13-R14.

Picture of the project:


Paraphase Tone Controller Circuit

The first is for the high frequencies (treble) response, the second, for the low frequencies (bass). The roll-off points have been selected, in combination with C4 and C8, for the sum of the two output signals to re-appear with a ‘straight’ frequency response again at the output. Roughly equal output levels from the networks are ensured by R6 = 7.15 k and R8 = 6.80 k. However, the operating principle requires the input signals to the two networks to be in anti-phase. For best operation the networks are driven by two buffers providing some extra gain.

Circuit diagram:


Paraphase Tone Controller Circuit Diagram

The gain of IC1.D is slightly higher than that of IC1.C to ensure the overall response curve remains as flat as possible at equal settings of the tone controls. Because each network introduces a loss of about 1.72 (times), IC1.D and IC1.C first amplify the signal. The gain is set at about 8 (times) allowing input signal levels up to 1 V to pass the circuit at maximum gain and distortion-free. The gain also compensates the attenuation if you prefer to keep the tone controls at the mid positions for a straight response.

Parts and PCB layout:


Parts and PCB Layout

To audio fans, the circuit is rewarding to experiment with, especially in respect of the crossover point of the two networks. R3 and R4 determine the control range, which may be increased (within limits) by using lower resistor values here. The values shown ensure a tone control range of about 20 dB. IC1.B buffers the summed signal across R15. C9 removes any DC-offset voltage and R16 protects the output buffer from the effects of too high capacitive loads. R17, finally, keeps the output at 0 V. The choice of the quad opamp is relatively uncritical. Here the unassuming TL074 is used but you may even apply rail to rail opamps as long as they are stable at unity gain. Also, watch the supply voltage range. A simple circuit board was designed for the project. Linear-law potentiometers may be fitted directly onto the board. Two boards are required for a stereo application. The relevant connections on the boards are then wired to a stereo control potentiometer.


  • Current consumption (no signal) 8 mA
  • Max. input signal 1 Veff (at max. gain)
  • Gain at 20 Hz +13.1 dB max. –6.9 dB min.
  • at 20 kHz +12.2 dB max. –7.6 dB min
  • Gain (controls at mid position) 2.38 x
  • Distortion (1 Veff, 1 kHz) 0.002% (B = 22kHz) 0.005% (B = 80 kHz)



R1-R4 = 10k
R5,R7 = 1k
R6 = 7k15
R8 = 6k80
R9,R10,R11 = 8k2
R12,R13,R14 = 2k2
R15 = 1M
R16 = 100R
R17 = 100k
P1,P2 = 100k preset or chassis-
mount control potentiometer, linear law
C1,C2,C3 = 47nF MKT, lead pitch 5mm
C4 = 68nF MKT, lead pitch 5mm
C5,C6,C7 = 10nF MKT, lead pitch 5mm
C8,C10,C11 = 100nF MKT, lead pitch 5mm
C9 = 2µF2 MKT, lead pitch 5mm or 7.5mm
IC1 = TL074
K1,K2 = line socket, PCB mount, e.g.
T-709G (Monacor/Monarch)

Author: Ton Giesberts - Copyright: Elektor Electronics

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Sensitive Audio Power Meter

As a follow-up to the simple audio power  meter described in [1], the author has developed a more sensitive version. In practice,  you  rarely  use  more  than  1 watt  of  audio  power in a normal living-room environment.  The only time most people use more is at a  party when they want to show how loud their  stereo system is, in which case peaks of more  than 10 W are not uncommon. With this circuit, the dual LED starts to light up  green at around 0.1 watt into 8 ohms (0.2 watt  into 4 ohms). Naturally, this depends on the  specific type of LED that is used.
Circuit diagram:
Sensitive Audio Power Meter-Circuit-Diagram
Sensitive Audio Power Meter Circuit Diagram
Here it is  essential to use a low current type. The capacitor is first charged via D1 and then discharged via the green LED. This voltage-doubler effect  increases the sensitivity of the circuit. Above a level of 1 watt, the transistor limits the current through the green LED and the red LED con ducts enough to produce an orange hue.The red colour predominates above 5 watts. Of course, you can also use two separate ‘normal’ LEDs. However, this arrangement cannot generate an orange hue. For any testing that may be necessary, you should use  generator with a DC-coupled output. If there is a capacitor in the output path, it can cause misleading results.
Reference: Simple Audio Power Meter, Elektor July & August 2008. 
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1997 Chevrolet Blazer Electrical Wiring Diagram

1997 Chevrolet Blazer Electrical Wiring Diagram
The Part of 1997 Chevrolet Blazer Electrical Wiring Diagram: Cruise Control System, Defogger, Rear
Glass Release, Rear Wiper/Washer, Shift Interlock System, Transmission System, 6-Way Power Seat Circuit, A/C Circuit, etc. Computer Data Lines, Anti-lock Brake, Back-up Lamps Circuit, Charging Circuit, Keyless Entry, Engine Performance Circuits, Warning System, Courtesy Lamps, Door Lock Circuit, Electronic Transfer Case Circuit, Exterior Lamps, Front Wiper/Washer, Starting Schematics, Supplemental Restraint, Sealed Beam Headlamps, Horn, Instrument Cluster Circuit, Instrument Illumination, Power Distribution Circuit, Headlight, Ground Distribution, Power Mirror, Power Window, Power Window Diagram, Features: Power windows, power door locks, anti-lock braking, dual air bag, power mirrors, cruise control, air conditioner, AM-FM stereo radio with CD, 4.3-liter Vortec V-6 engine, four-speed automatic gearbox.
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1969 Pontiac Firebird Electrical Wiring DIagram

1969 Pontiac Firebird Electrical Wiring DIagram
The Part of 1969 Pontiac Firebird Electrical Wiring DIagram: down shift switch solenoid, neutral safety switch, backup light switch, stop light switch, coil, breaker, oil press switch, alternator, horn, high beam headlamp, low beam headlamp, parking light, directional signal, marker light, starter, alternator regulator, idle solenoid, wiper motor, battery, parking light, directional signal, windshield washer solenoid, buzzer.
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Wednesday, April 10, 2013

How to Make a Simple Peltier Refrigerator at Home

We are all familiar with a Peltier device and know how it functions.

Basically it works on the principle of thermo-electric effect (opposite of Seebeck Effect) where a potential difference is used for making or producing hot and cold temperatures over the two ends of a dissimilar metal assembly.

More innovative circuits HERE.

A Peltier device has two terminals in the form of wire ends which requires to be connected across a voltage source rich in current content.

The application of voltage instantly starts transforming one surface of the unit hot and the reverse surface cool very fast.

However, the hot end must be quickly managed so that the heat does not reach higher levels, which can completely hamper the heating and cooling process and ruin the device itself.

Therefore the hot surface must be attached with heavy heatsinking materials like aluminum or copper metal of suitable sizes.

The simple construction of a simple peltier refrigerator shown in the figure demonstrates the above discussed set up where two such devices are appropriately fixed with aluminum plates for radiating different degrees of temperatures from their relevant sides.

The plates responsible for generating the cooling effects must be trapped inside a well insulated enclosure made up of thermocole or polyurethane foam etc.

The inside chamber may be used for storing water bottles or water packets as desired.

The hot heatsinked surfaces must be exposed in the outside air for radiations and for controlling the temperatures of "hot" ends of the unit, see figure.

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Junk box Fan Speed Controller

My new home theatre receiver was getting rather hot in the close confines of its cabinet, with the temperature reaching over 40°C after only about 30 minutes of use. To help lower the temperature, I decided to install a fan in the cabinet. A 75mm hole was cut in the shelf under the receiver, and a 12V fan salvaged from an old computer power supply was mounted underneath. The fan was powered from a 12V DC plugpack. 

This did the job, keeping the temperature below 30°C even after prolonged use on a warm day. However, the fan was annoyingly loud when running at full speed. To reduce the noise level substantially, I built this fan speed controller with temperature feedback. The circuit was culled from variety of ideas found on various sites on the internet, with the final circuit designed from what was in the "junk box". Air temperature in the cabinet is sensed via an LM335 (TS1).

Circuit diagram:
junk-box-fan-speed-controller circuit diagram
Junk-box Fan Speed Controller Circuit Diagram

It is glued to a piece of aluminium about 25mm square with instant glue, which is then attached to the top of the receiver with "Blue-Tack". About 300mm of audio coax makes the connection back to the circuit board. The LM335’s output rises 10mV per degree Centigrade. It is calibrated to zero output at -273°C, so at 20°C, the output will be 2.93V. This is applied to the non-inverting input of a 741 op amp (IC1). A 1N4733 5.1V Zener diode provides a voltage reference for the inverting input via trimpot VR1. The output of the op amp drives a TIP122 Darlington transistor (Q1), which in turn drives the fan motor. The op amp gain was calculated to give about 12V to the fan at 40°C. 
To keep the transistor cool, it is mounted on the metal base of a small plastic box, which is also used to house the components.  Initial setup should be performed with everything turned off and the ambient temperature at about 20°C. Adjust the 10-turn pot until the fan just stops running. I used a gasket made from foam strips and "blue-tacked" them between the feet of the receiver to direct all of the airflow through it. The temperature now remains at about 32°C, the fan runs very quietly and continues to run down for about 30 minutes after the receiver is switched off.
Source by : Streampowers
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Mains Slave Switcher II

As a guide, a one-inch reed switch with 40 turns reliably switched on with the current flowing through a 150-watt lamp (approx. 625 mA) but larger reeds may require more turns. If the master appliance draws less current (which is unlikely with power tools) more turns will be required. The reed switch is used to switch on transistor T1 which in turn switches the relay RE1 and powers the slave appliance. Since reed switches have a low mechanical inertia, they have little difficulty in following the fluctuations of the magnetic field due to the alternating current in the coil and this means that they will switch on and off at 100 Hz.

Circuit diagram:
mains-slave-switcher-circuit diagram
Mains Slave Switcher II Circuit Diagram

C3 is therefore fitted to slow down the transistor response and keep the relay energised during the mains zero crossings when the current drawn by the appliance falls to zero and the reed switch opens. C1 drops the mains voltage to about 15 V (determined by zener diode D1) and this is rectified and smoothed by D2 and C2 to provide a d.c. supply for the circuit. The relay contacts should be rated to switch the intended appliance (vacuum cleaner) and the coil should have a minimum coil resistance of 400 R as the simple d.c. supply can only provide a limited current. C1 drops virtually the full mains voltage and should therefore be a n X2-class component with a voltage rating of at least 250V a.c.

The circuit is by its nature connected directly to the mains supply. Great care should therefore be taken in its construction and the circuit should be enclosed in a plastic or earthed metal box with mains sockets fitted for the master and slave appliances.
Source by : Streampowers
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Acoustic Distress Beacon

An ELT (Emergency Locator Transmitter, also known as a distress beacon) is an emergency radio transmitter that is activated either manually or automatically by a crash sensor to aid the detection and location of aircraft in distress. This acoustic ELT project is intended for radio control (RC) model aircraft, which every now and then decide to go their own way and disappear into the undergrowth.
Circuit diagram :
Acoustic Distress Beacon-Circuit Diagram
Acoustic Distress Beacon Circuit Diagram

The audio locating device described here enables model aircraft that have landed ‘off limits’ to be found again and employs its own independent power supply. The small cam-era battery shown in the circuit activates an acoustic sounder when radio contact is lost and produces a short signal tone (bleep) every ten seconds for more than 25 hours. Current consumption in standby and passive (with jumper J1 set) modes is negligible. The timing generator for the alarm tone is the Schmitt trigger AND-gate IC1.B; its asymmetric duty cycle drives a 5 V DC sounder via MOSFET transistor T1. All the time that the RC receiver output is delivering positive pulses, the oscillator is blocked by IC1.A and diode D1. Setting jumper J1 parallel to C2 also disables the oscillator and serves to ‘disarm’ the distress beacon. 

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Automatic Dark Activated LED Light Circuit Diagram using 555 Timer

Automatic Dark Activated LED Light Circuit Diagram using 555 Timer
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DC Motor Speed Controller

This circuit takes advantage of the voltage drop across bridge rectifier diodes to produce a 5-position variable voltage supply to a DC fan or other small DC motor. It is not as efficient as a switch-mode circuit but it has the virtues of simplicity and no switching hash. The four full-wave bridges are connected so that each has two pairs of series diodes in parallel, giving a voltage drop of about 1.4V, depending on the load current.

Circuit diagram:
dc-motor-speed-controller-circuit diagram
DC Motor Speed Controller Circuit Diagram

The rotary switch should have "make before break" contacts which should be rated to take currents up to about an amp or so. For higher currents, higher rated bridge rectifiers and a suitably rugged rotary switch (or solenoids) will be required. If you want smaller voltage steps, you could use the commoned AC inputs on the bridge rectifiers to give intermediate steps on the speed switch.
Source by : Streampowers
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Car Boot Lamp Warning ICM7556

On many cars, the boot light will not go out until the lid is properly closed. It is all too easy when unloading the car, to leave the lid ajar. If you are unlucky and the car remains unused for some time, the next time you try to start it, the lamp will have drained the battery and you will no doubt utter a few appropriate words. The circuit described here will give a warning of just such a situation.

A mercury tilt switch is mounted in the boot so that as the lid is closed, its contacts close before the lid is completely shut. The supply for the circuit comes from the switched 12 V to the boot lamp and through the mercury switch. When the lid is properly closed, the boot lamp will go out and the supply to the circuit will go to zero. If however the lid is left ajar, the lamp will be on and the mercury switch will close the circuit.

Car Boot Lamp Warning Circuit Diagramw

After 5 seconds, the alarm will start to sound, and unless the lid is shut, it will continue for 1 minute to remind you to close the boot properly. The 1-minute operating period will ensure that the alarm does not sound continuously if you are, for example, transporting bulky items and the boot will not fully close. The circuit consists of a dual CMOS timer type 7556 (the bipolar 556 version is unsuitable for this application). When power is applied to the circuit (i.e. the boot lid is ajar) tantalum capacitors C1 and C2 will ensure that the outputs of the timers are high. After approximately 5 seconds, when the voltage across C2 rises to 2/3 of the supply voltage, timer IC1b will be triggered and its output will go low thereby causing the alarm to sound.

Meanwhile the voltage across C1 is rising much more slowly and after approximately 1 minute, it will have reached 2/3 of the supply voltage. IC1a will now trigger and this will reset IC1b. The alarm will be turned off. IC1a will remain in this state until the boot lid is either closed or opened wider at which point C1 and C2 will be discharged through R6 and the circuit will be ready to start again. To calculate the period of the timers use the formula: t = 1.1RC Please note that the capacitor type used in the circuit should be tantalum or electrolytic with a solid electrolyte. The buzzer must be a type suitable for use at D.C. (i.e. one with a built in driver).

Source : www.extremecircuits.net

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Fuse Box Toyota 93 Camry 2200 Diagram

Fuse Box Toyota 93 Camry 2200 Diagram - Here are new post for Fuse Box Toyota 93 Camry 2200 Diagram.

Fuse Box Toyota 93 Camry 2200 Diagram

Fuse Box Toyota 93 Camry 2200 Diagram
Fuse Box Toyota 93 Camry 2200 Diagram

Fuse Panel Layout Diagram Parts: ABS ECU, door lock control relay, cooling gan ECU, center air bag sensor, fuse/relay block, integration relay, A/C amplifier, shift lock control ECU, daytime running light relay,fuse relay, engine control module, electronic control transmission ECU, junction block, cruise control ECU.
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System circuit not Minimum Evaluation Board AT89C2051 and AT89C4051

Maybe we are more familiar with the term Minimum System AT89C2051 circuit, but this time I present a circuit which is not only a series of Minimum System AT89C2051 but more than that.
System circuit (not) Minimum (Evaluation Board) AT89C2051 and AT89C4051

The circuit is more deserves to be called Evaluation Board AT89C2051 and AT89C4051. Some of the advantages of circuit Minimum System AT89C2051 / AT89C2051 and AT89C4051 Evaluation Board which I was present this time, hardware-hardware support below:

RS-232 interface, DB-9
Header for LCD display
I2C, PCF8574 I / O extender
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Tuesday, April 9, 2013

USB Charger For Lithium Ion battery

USB Charger For Lithium Ion battery
USB Battery Charger For Lithium Ion battery with the LM3622 is a series of lithium ion battery charger. This charger circuit operates using power from the USB source PC.

Current consumption of a series of USB Battery Charger For Lithium Ion battery with 400mA LM3622 is limited by R1, so it does not exceed the current maximum limit that can be given by a USB computer. Brains from USB Battery Charger For Lithium Ion battery with IC LM3622 , it is a national of having special technical specification charger for lithium ion batteries.

usb battery charger

In a series of USB Battery Charger For Lithium Ion with LM3622 R1 0.25 Ohm value that serves to limit the charging current 400mA to the battery. Q2 and Q1 is the last part of the USB Battery Charger For Lithium Ion battery with the LM3622. In principle, USB Battery Charger For Lithium Ion with LM3622 identify the condition of the battery full charged battery voltage via pin 6 LM3622. USB Series Lithium Ion Battery Charger For LM3622 is equipped with a switch to select the battery that was in charge of 2.7 volts or 2.1 volts.
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Subwoofer Pre Amp Filter

Acoustic spectrum is extended by the 20Hz frequency is very low and reaches as high frequency 20000Hz. In the low frequency is lowered sense of direction. This reasoning leads us to attribute to the speakers use of very low frequency. Making it to you we propose to distinguish these frequencies, in order for him to lead us on a suitable amplifier.
Acoustic filter are met at different points in the sound system. Applications knownest they are filter baxandal to organize low-and high-frequency tones and crossover filter where the acoustics are separated in the subareas, for it leads to the appropriate speakers. Applications that you can we propose is a simple filter that limits the acoustic region (20-20000Hz) in 20-100Hz region.

With manufacturing, we propose that you can you can make an active filter for you lead a very low frequency loudspeaker. With this you will put a big one between speaker HIFI speakers from you. In order for you to have a complete picture of sound you will need also an appropriate amplifier. In the entry of circuit you will connect the two roads out of the preamplifier or the exit of the preamplifier few.

The series production in order to allocate out of the facility led a series of subwoofer power. If for some reason you do not have space for you to put the third speaker in the courtroom, then you can choose a smaller speaker. This output will depend on the type of music that you hear. If in deed you have the space, then after you create a filter and still say thank you, you can he recommend your friends or still makes each other to your friends.
Circuit diagram

Filter | PreAmp Subwoofer
Filter | PreAmp Subwoofer circuit diagram


R1 = 39 Kohm , R2 = 39 Kohm,R3 = 47 Kohm,R4 = 10 Ohm,R5 = 22 Kohm,R6 = 4.7 Kohm,R7 = 22 Kohm, R8 = 4.7 Kohm, R9 = 10 Ohm, R10 = 220 Ohm, C1 = 39 pF,C2 = 0.1 UF,C3 = 0.1 UF, C4 = 0.2 UF, C5 = 0.4 UF, C6 = 0.1, UF C7 = 0.1 UF, IC1 = TL064

In the form that appears theoretical filter circuit. At first glance we see three different circuits which are mainly produced by two rounds of operational amplifiers. This circuit is a mixture, with the assistance variable amplifier and variable filters. Late-making requires a series of operations catering catering with the same trend with  ± 12. operational amplifier which is the active element for this circuit is the type of dual operation as a TL082 and NE5532

The operational amplifier is included in a family is equipped with field-effect transistor IFET in their entries. Each member is allocated a family in bipolar transistor circuits and field effect. This circuit can function in a high inclination, because of their high propensity to use transistors. Also they have the high honor rhythm elevation (slew rate), low polarization at this time for entry and little influenced by temperature. The operational amplifier has an area of 3MHz unity gain bandwidth. Another important element for them is a great choice reject noise, there are currently in the line of catering.

Price refused to greater than 80dB, their consumption is small, from 11 to 3 mA. They briefly sold internally with eight pins and allocate two operational amplifiers, In the same row 14 pin in short they combine four operations, the trade them for sale with code TL074, TL084 and TL064, a nutshell with eight pins they sold the operational amplifier TL071 TL061 kajTL081 . In manufacturing we use the TL082 that has two operational. First operation of TL082 he worked as an amplifier and mixed with two channels, the entry is negative, it is a little mixed with the two resistances. A potentiometer on the steps of determining the aid circuit. At this point the left wing and right-channel preamplifier they added means of two resistances. En operational continuity with the help strengthen the signal is made depending on the price that has been potentiometer.

Filter | PreAmp Subwoofer
PCB layout

Place runner comparable with the assistance of the circuit. The second operational amplifier is a filter manufacturing. Filters from the acoustic frequency from second grade and he made a round of operational amplifiers. This filter section with variable frequency low-cut. This frequency can be changed and took the price of very low frequency of 30Hz or still exceeds 150Hz. The frequency of the filter depends on the price cuts that have circuit elements. Change the value of the elements that we can have a frequency cut 150Iz, 130Hz, 100Hz, 7A? Z, 6A? Z even 3A? Z, is the price that they can be achieved by simple rotation of the double potentiometer. Filter circuit has been made about an operation that has completed a TL082 dual operational amplifier. In the filter out we will connect the plug load which is connected amplifier. In a series of exit are presented, which are limited as to the extent of frequency, the signal applied in the entry of the circuit.
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Two Wire Temperature Sensor

The Type LM35 temperature sensor from National Semiconductor is very popular for two reasons: it produces an output voltage that is directly proportional to the measured temperature in degrees Celsius, and it enables temperatures below zero to be measured. A drawback of the device is, however, that in its standard application circuit it needs to be connected to the actual measuring circuit via a three-wire link. This drawback is neatly negated by the present circuit. When the LM35 is connected as shown, a two-wire link for the measurement range of –5 °C to +40 °C becomes possible.

Two-Wire Temperature Sensor Circuit DiagramActually, the circuit shown is a temperature-dependent current source, since it uses the variation of the quiescent current with changes in temperature. The values of resistors R3 and R4 are calculated to give an output voltage of 10mV °C–1. Where good accuracy is desirable or necessary, 1% resistors should be used. In this context, note that a loss resistance in the link between sensor and measuring circuit may cause a measurement error of about 1 °C for every 5 ohms of resistance. Capacitor C1 eliminates undesired interference and noise signals. At an ambient temperature of 25 °C, the circuit draws a current of about 2mA.
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Room Noise Detector Schematic Circuit

This circuit is intended to signal, through a flashing LED, the exceeding of a fixed threshold in room noise, chosen from three fixed levels, namely 50, 70 & 85 dB. Two Op-amps provide the necessary circuit gain for sounds picked-up by a miniature electret microphone to drive a LED. With SW1 in the first position the circuit is off. Second, third and fourth positions power the circuit and set the input sensitivity threshold to 85, 70 & 50 dB respectively. Current drawing is 1mA with LED off and 12-15mA when the LED is steady on.

Circuit diagram :

Room Noise Detector Circuit diagram

Parts List :

R1____________10K 1/4W Resistor
R2,R3_________22K 1/4W Resistors
R4___________100K 1/4W Resistor
R5,R9,R10_____56K 1/4W Resistors
R6_____________5K6 1/4W Resistor
R7___________560R 1/4W Resistor
R8_____________2K2 1/4W Resistor
R11____________1K 1/4W Resistor
R12___________33K 1/4W Resistor
R13__________330R 1/4W Resistor

C1___________100nF 63V Polyester Capacitor
C2____________10µF 25V Electrolytic Capacitor
C3___________470µF 25V Electrolytic Capacitor
C4____________47µF 25V Electrolytic Capacitor

D1_____________5mm. Red LED

IC1__________LM358 Low Power Dual Op-amp

Q1___________BC327 45V 800mA PNP Transistor

MIC1_________Miniature electret microphone

SW1__________2 poles 4 ways rotary switch

B1___________9V PP3 Battery

Clip for PP3 Battery

Use :
  • Place the small box containing the circuit in the room where you intend to measure ambient noise.
  • The 50 dB setting is provided to monitor the noise in the bedroom at night. If the LED is steady on, or flashes bright often, then your bedroom is inadequate and too noisy for sleep.
  • The 70 dB setting is for living-rooms. If this level is often exceeded during the day, your apartment is rather uncomfortable.
  • If noise level is constantly over 85 dB, 8 hours a day, then you are living in a dangerous environment.

Source by : Streampowers
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