Blown-Fuse Indicator

 This is a blown-fuse indicator for a dc power supply. When the fuse is intact, the transistor is base-biased into saturation. This turns on the green LED to indicate that all is OK. The voltage between point A and ground is approximately 2 V. This voltage is not enough to turn on the red LED. The two series diodes (D1 and D2) prevent the red LED from turning on because they require a drop of 1.4 V to conduct.When the fuse blows, the transistor goes into cutoff, turning off the green LED. Then, the voltage of point A is pulled up toward the supply voltage. Now there is enough voltage to turn on the two series diodes and the red LED to indicate...

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Battery Charger, Volatge and Current Control

This project is not so important for those who ride a car every day. In my case, a car is not used every day. In that case, the voltage of a battery is falling and a car sometimes cannot be put into operation. If the battery itself is left for a long period of time, the electricity of it will be lost by natural electric discharge. Furthermore, in the case of the latest car, various kinds of electric devices are always backed up more often with a battery. Therefore, even when the car is not being used, the electricity of a battery is consumed little-by-little. I was creating and using the battery charger which used the solar battery before....

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INFRA RED TEST RECEIVER by: Dmohankumar

This circuit can operate a load such as LED, Buzzer or Relay for a period of  3 minutes through a Remote hand set. It uses the IR sensor module TSOP 1738 which operates in 38 KHz Infrared pulses. The circuit is a Short duration Monostable  using 555 timer IC. Its trigger pin 2 is connected to the output of the IR sensor through R2 and LED. Normally the output of  IR sensor is low. But the timer IC will not be triggered because its trigger pin remains high through R3. When the remote hand set is focused on to the IR sensor and any one of the buttons is pressed, out put of IR sensor goes low and triggers the 555 IC. With the given...

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NON-CONTACT POWER MONITOR

NON-CONTACT POWER MONITOR By: D. MOHAN KUMAR   Here is a simple non-contact AC power monitor for home appliances and laboratory equipment thatshould remain continuously switched-on. A fuse failure or power breakdown in the equipment going unnoticed may cause irreparable loss. The monitor sounds an alarm on detecting power failure to theequipment. The circuit is built around CMOS IC CD4011 utilising only a few components. NAND gates N1 and N2 of the IC are wired as an oscillator that drives a piezobuzzer directly. Resistors R2 and R3 and capacitor C2 are the oscillator components. The amplifier comprising transistors T1 and T2 disables...

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Dual Audio Analog Switches

FEATURES “Clickless” Bilateral Audio Switching Guaranteed “Break-Before-Make” Switching Low Distortion: 0.003% typ Low Noise: 1 nV/√Hz Superb OFF-Isolation: 120 dB typ Low ON-Resistance: 60 V typ Wide Signal Range: VS = 618 V; 10 V rms Wide Power Supply Range: 620 V max Available in Dice Form GENERAL DESCRIPTION  The SSM2402/SSM2412 are dual analog switches designed specifically for high performance audio applications. Distortion and noise are negligible over the full audio operating range of 20 Hz to 20 kHz at signal levels of up to 10 V rms. The SSM2402/ SSM2412 offer a monolithic integrated alternative to...

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How to Made Double Voltage

A voltage multiplier in its most basic sense works on the principle that "A CAPACITOR IS A CAPABLE OF STORING CHARGE AND THAT IT HAS THE SAME POTENTIAL AS THE SOURCE WHICH CHARGED IT". Now, the whole idea is that in an AC system you use capacitors in such a way that the net output voltage should be, say double of what you would otherwise get. This circuit will be called a voltage doubler. Now lets have a look at the action that actually happens to double the voltage.   The image you see is a schematic of a voltage doubler, few things to notice about it. The transformer gives output between points A and B. The load is connected...

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Electronics TL-Lamp 12 volt DC

By David Bradbury The circuit shown in Figure below has been designed to drive an 8Wfluorescent lamp from a 12V source, using an inexpensive inverter based on the ZTX652 transistor. The inverter will operate from supplies in the range of 10V to 16.5V, attaining efficiencies up to 78% thus making it suitable for use in on-charge systems such as caravans / mobile homes/ RVs as well as periodically charged systems such as roadside lamps, camping lights or outhouse lights etc. Other features of the inverter are that it oscillates at an inaudible 20kHz and that it includes reverse polarity protection. Circuit Operation The 270W and 22W resistors...

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