Free electronic circuit design and schematic diagram
Stepper motor controller is needed to run a stepper motor, since a stepper motor cannot work by just connecting it to a power supply. To program a stepper motor to make a complex movement, we usually need a micro controller. Fortunatelly, for a simple movement like just rotating eith a constant speed, we can use avery simple circuit as described […]
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This testing instrument provide two alternate fuction: signal injector and signal tracer. This audio signal tracer/injector is very helpful in trouble shooting audio circuits, when you need to test a circuit by injecting a signal and observe the output (by watching the oscilloscope or by hearing the loudspeaker for example), or by tracing some points inside the circuit when an […]
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UHF antenna booster can be used for better reception, especially when you’re far from TV station / relay transmitter. This UHF antenna booster works in 400-850 MHz range. Here is the circuit diagram of the UHF antenna booster: The circuit use only one transistor, but it gives you 10 to 15 dB amplification, enough for many situation. The most important […]
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LED flasher circuit here will flash a LED using only 1.5 volts supply voltage. Normally, to make any LED lamp works, you need more than 2 volts power supply. This because LED will work only when the supply voltage is higher than its forward bias voltage, around 2 volts for red LED, and slightly lower for other color (but still […]
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This FM transmitter circuit is small, similar to our previous single chip FM transmitter, but this FM transmitter is monophonic. You can see in the circuit’s schematic, the left and right signals is mixed before modulate the radio frequency. Here is the schematic diagram of the circuit: The core of this FM transmitter circuit is a MAX2606 IC chip, […]
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This antenna booster circuit can be used to amplify the weak signal received by the antenna. Antenna for AM/FM is usually not tuned for the optimal dimension of 1/4 wavelength, since we prefer small portable size. This untuned antenna has very low gain, so the antenna booster circuit here is very helpful in getting better signal reception. Here is the […]
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pH Meter Circuit pH meter measures the voltage (the EMF, electromotive force) generated by the pH electrodes (the sensor) to show the hydrogen concentration in pH scale. Basically, a pH meter is nothing more than a pH probe/sensor with high impedance voltmeter that measures the generated voltage at the pH probe. To measure the pH with a standard digital voltmeter […]
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