This circuit was obtained in an American documentation from the 80's. The transistors can be equivalent to those indicated and the crystal can reach a few tens of megahertz.
This circuit consists of two stages that each shift 180 degrees the signal. The circuit was...
This simple battery tester uses two transistors to drive LEDs of different colors, indicating the...
Found in 90s documentation from Analog Devices, this circuit employs operational amplifiers of the time....