Author: misamaliraza94
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Li-Ion Battery Charger
A lower charging current just brings about a correspondingly longer charge time. IMHO 100mA is quite low, low enough that the circuit can be used for an overnight charger for many typical single-cell li-ion batteries. The resistors are deliberately kept at large orders of magnitude (tens/hundred Kohm and Mohm range) to keep the off-state current…
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Battery Juicer
More and more electronic devices are portable and run off batteries. It is no surprise, then, that so many flat batteries find their way into the bin – and often far too early. When a set of batteries can no longer run some device – for example, a flashgun – the cells are not necessarily…
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Lights On!
This circuit ensures that you will never again forget to switch on the lights of your car. As soon as the engine is running, the dipped beams and the sidelights are automatically switched on. The circuit also causes the dipped beams to be extinguished as soon as the main beams are switched on. As you…
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Lambda Probe Readout For Carburettor Tuning
A lambda probe (or oxygen sensor) can be found on the exhaust system of most cars running on unleaded fuel. Having reached its normal operating temperature (of about 600 degrees Celsius!) the lambda probe supplies an output voltage proportional to the amount of residual oxygen measured in the exhaust gas. This information is indicative of,…
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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…
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Car Battery Saver
Prevents the complete discharge of the battery when the door is left open accidentallyI recently forgot to close the door of my car after parking in the garage and I found the battery completely exhausted after the week-end, when I tried to start the engine on Monday morning. This inconvenience prompted me to design a…
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Brake Light Signal Module
Generates 4 short flashes, followed by a steady on lightCan drive LED Arrays at currents up to 1 Amp Circuits of this kind are intended to drive LED Arrays in order to create more visibility and conspicuity when a vehicle is stopped or stopping. This circuit, in particular, will emit a visual alerting signal of…
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General Purpose Oscillator
The oscillator shown in Figure1 is frequently used in digital circuits and may, therefore, look very familiar. Many readers may not know that this type of oscillator suffers from a nasty draw-back caused by noise. When the amplitude of the noise is higher than the hysteresis of the gates used for the oscillator, spurious switching pulses are…
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Multi-Sound For Guitars
Electric guitars use coils (guitarists call them pickups or elements) to convert the vibrations of the strings into an electrical signal. Usually, a guitar has more than one element builtin, so that the musician can select with a switch which element or elements are used to generate the signal. Because of the differences in construction…
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US-Style Siren
The circuit described here can create three different ‘US-style’ siren sounds: police, ambulance and fire engine. The desired sound can be selected using switch S1. The circuit can be used in toys (such as model vehicles), as part of an alarm system, and in many other applications. For use in a toy, a BC337 is…