Sound Controlled Activated Triggered LED

When the microphone detects a loud sound, this circuit will turn the LED on. The “charge-pump” section consists of the 100n, 10k, signal diode and 10 uF electrolytic.   Here is the schematic diagram of the circuit: The charge pump section has two functions: rectifying and multiplying  the signal voltage. To illuminate the LED, a signal on the collector of the […]

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Touch Sensitive LED

Below is the simplest circuit you can get. We can use any NPN. Connect the 220 ohm resistor, LED and transistor as shown in the figure below. Touch the top point with two fingers of one hand and the lower point with fingers of the other hand nad squeeze. When you squeeze harder, the LED will turn on brighter. We […]

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