This circuit is for traditional old-style telephone lines found in an American 1980s documentation. Components are common and the optical coupler can be replaced with an equivalent.
This circuit controls a relay in a bistable way by touching the sensors type NF (CH3) and NO...
This circuit produces modulated tones in a loudspeaker. The effects can be adjusted by the...
This is a simulation of a Relaxation Oscillator using a programmable unijunction transistor (PUT). The...