This oscillator for the fifth overtone of a crystal was found in a Radio Electronics magazine from May 1970. Transistors are RF types, and the transistor determines the maximum frequency achieved.
This circuit is intended to apply the music signal from a stereo to a telephone line for the...
This tachometer from a 1994 publication has a bargraph scale with the well-known LM3914 integrated...
This traditional triplier configuration with the 555 can be found in other articles on the...