Found in a 90s American documentation, this circuit that was used in cars of the time, detects low temperatures and light by activating a warning relay.
This control for 1200 W of power was found in the documentation of General Electric of 1966 has a...
I found this circuit in an old English magazine from 1979, but it can be easily assembled with...
This circuit imitates the singing of a bird intermittently with the intermittency determined by C1...