LED VU Meter circuits using transistors, 5 to 20, 40 LED
See LED VU meter using transistor is analog circuit to show the level of power audio signal. You can build 5 LED to 20 LED display with PCB.
NPN transistor circuit
How does a transistor circuit works
Learn transistor circuit works, old parts But, we often use it. Because of durable, high current. Whether any reason. Let’s learn they works in simple way.
Lie detector circuit
See and try building Lie detector circuit. The resistance of human skin using transistors and LED displays is small and easy application.
Very simple amplifier circuit using transistor 2N3904
It is Very simple amplifier circuit using transistor 2N3904 only, low noise than normal IC circuits, low distortion,frequency response: 20 Hz to 20 kHz.