4QD manufacture motor speed controllers so all our H bridges are PWM. Here`s a simple switch circuit for reversing and stopping a motor without any control of speed. Two inputs, A and B, control the bridge. With both high (or open circuit) both ends of the....

An interesting circuit of a true-portable and cute solid-state bright light built with LT1932. The light can be operated from two AA size dry/rechargeable pen-light cells. There is no housing included so that you can use your own imagination as to what you....

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To operate car audio (or video) system from household 230V AC mains supply, you need a DC adaptor. DC adapters available in the market are generally costl....

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Application note on how to design linear and switch-mode (switching dc-dc converter current source) battery charger applications that require external microcontrollers and related system-level issues for notebook computers....

This is a design for a high impedance DC voltmeter. This circuit is design with built by uA741 IC. This IC is a op-amp non-inverting DC amplifier. The IC have negative feedback that is through a DC meter requiring 1mA for full scale deflection. This is the....

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The main purpose of this design was to obviate a small defect of the very popular Fridge Door Alarm circuit, available on this website since 1999 and built by a lot of hobbyists. Unfortunately, that circuit stops operating when the battery voltage falls....

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As you can see on the circuit, a class AB audio amplifier IC requires only a few external components. And this series is also very easy to build. 10W stereo amplifier circuit requires a stable power supply with a voltage of 18 V and 1A current needs. ..

Want to make a set of attention-getting LED running lights? This article provides a circuit diagram and discussion of the CMOS logic and IC layout for a simple sequential LED flasher or light chaser that one can build, including the parts lists. The heart of....

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Charge NiCd or NiMH batteries with solar cells. This circuit extracts the maximum power from a solar array to charge a battery stack. It employs the MAX856 boost converter and MAX982 dual comparator with reference. As a power source, the sun offers some....

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The Hartley Oscillator is characterised by an LC circuit in its collector. The base of the transistor is held steady and a small amount of signal is taken from a tapping on the inductor and fed to the emitter to keep the transistor in oscillation...

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Hi Sluts! long time lurker here, a while ago i bought 4 of those old amps for the case, and with my limited knowledge of old equipement, i never realy....

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A unit which is often very useful, if we need to isolate, in sound circuits, two stage between them. Then we can use this circuit which has an amplified unit, which gain X1, we do not use total negative feedback, only local, with the result that distortion....

The Hakkit robotics shield is a breakout kit for the Arduino Uno R3. When assembled the shield gives five standard servo headers taking advantage of the PWM pins on the Arduino and breaks out the analog pins to give six inputs for sensors. This shield is the....

Simple voltage probe circuit shown in the schematic diagram below very useful in testing, testing, or troubleshooting discrete  or integrated circuits,....

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An LED - light emitting diode is used to illuminate keypads keys and LCD screen displays on all mobile phones handsets. It is being controlled by a voltage or current draws on its terminal leds. On schematic diagram we notice that the LEDs is driven by an....

This page provides links to software and hardware designs contributed by Handy Board users. If you would like to contribute some work of your own to the Handy Board community, please contact Fred Martin. Thanks! George Musser contributed an adaptation of....

These are circuits of high impedance low capacitance buffer and high impedance low capacitance? amplifier. First figure is a high impedance low capacitance...

A project called LED Flasher which Flashes LED`s one by one . but I have following Query about my project . if anyone can explain me it in simple words it will be great help for me . one can use Below image for reference or use this link..

This simple amplifier is ideal for adding a headphone jack to equipment that lacks this feature. The Headphone Buffer circuit board is small enough (1. 2" X 1. 4") to squeeze into even the smallest spaces and power requirements are so low that existing....

Strictly speaking, this simple circuit shouldn`t work! How could anyone expect an ordinary light dependent resistor photo cell to `see` through a fingertip in natural daylight and detect the change in blood flow as the heart pulsates The secret is a high....

Here is a simple and easy to make heat or temperature sensor alarm circuit. A good feature of this circuit is that it will produce beep-beep sound and flashes an LED according to the temperature....

A very high quality intercom, which may also be used for room monitoring..

A working circuit with an opamp but my professor said that they are hard to work with, and gave me some transistors to use instead. enthdegree May 30 `13 at 17:25..