This circuit with transistors of the time was found in the November 1972 Radio Electronics magazine. The circuit also generates a sawtooth signal for use on an oscilloscope.
This circuit was obtained from Popular Electronics in 1993. It consists of a low frequency...
The emitter of this circuit from a 1995 publication is an infrared LED and the sensors are...
This version of the circuit is from 2000, using a source of negative voltage that allows to obtain...