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.
Used with telephones at the time, this circuit was found in Popular Electronics from the 90s. The...
Unlike the CIR4620 circuit, the circuit shown in the figure operates by capacitance. This means...
This 1 A circuit was found in a Philips documentation from 1966. The transistor is of the time,...