This simple injector and signal follower employs a high impedance headset. Transistors can be of general use. The circuit is from old American documentation.
The LM567 is a PLL tone decoder that can also be used as a double oscillator as shown in the...
Originally designed to analyze the shape of light pulses from a flash for photographic...
This interesting control circuit was found in an Electronics Now from 1988. Through it we can...