LED Pilot Light using FET

This is the LED pilot light (or LED indicator) circuit. LEDs (Light Emitting Diode) part are interesting things. They only operate at DC supply within specific tolerances, and generally connected with a current limiting resistor towards the power source. Rather than a resistor, it is possible to use a FET (Field Effect Transistor) like the… Read More »

Lantern Dimmer and Flasher

Here is the circuit diagram of lantern dimmer / flasher designed by Tony Van Roon: There are two circuit modes: dimming and flashing. The flasher mode is useful for warning other drivers of your troubles and it may be adjusted to have a very short flash duration for long-term use as when the car must… Read More »

LED Flasher 2-Transistors

The following is LED Flasher circuit which use 2 transistors for LED switching. The circuit works similar to flip-flop operation. Components List: R1 = 10M ohm R2 = 1K – 100K ohm R3 = 470 ohm C1 = 0.47?F – 10?F/25V D1 = 1N914 Q1 = 2N3904 Q2 = 2N3906 Led = High Brightness Red… Read More »

Simple Mic Pre-Amp based LM358

Here the simple mic pre-amp circuit design based on single IC LM358. The circuit is very simple, inexpensive and easy to built. This mic pre-amplifier circuit operated with 9V DC voltage, you may use 9V battery for this circuit. Component Parts List: R1, R3, R4 = 10K R2 = 1K R5 = 100K-1M Potensiometer C1… Read More »

Maestro Boomerang Pedal

Here the circuit diagram of Maestro Boomerang pedal / Wah-Wah pedal for electric guitar effect. Note: Transistors Q1 and Q2 were designated P-2356. The Maestro Boomerang is not only a wide range wah wah pedal but also a volume pedal. It’s deemed as one of the best wah pedals ever built – and I totally… Read More »

Guitar Pre-Amp with JFET 2N5457

Designed by Don Tillman, this guitar pre-amp circuit design is dedicated for people who don”t like op-amps module. This circuit is a discrete JFET pre-amplifier design, use 2N5457 as the main component. It has low noise, low distortion, low feedback, overloads gracefully, is small, etc.

Simplest RF Transmitter

This is probably become the simplest radio frequency RF transmitter that you will find anywhere. It has a total of five parts and can be constructed into a very small space. It is great for science fair projects or other science related projects where short range transmission is useful. It operates on 1.5 to 3… Read More »

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