Found in a 1965’s Electronic Design, this circuit operates with a voltage of 1.5 V. The relay can be of a reed relay or other type.
The circuits below were found in amarican publication of the year 1958. The transistors are...
In a transmitter sequencer we have a high input impedance and a low output impedance. The voltage...
With the light falling on the LDR, the relay closes its contacts by activating a warning system. The...