Found in 1965s General Electric documentation, this circuit is intended for the control of servos connected to the power grid. Equivalent modern components can be employed.
This receiver with two common JFETs was found in an old English documentation. The phone is...
This TTL circuit with the 7493 makes the binary count of the pulses sent by a flip-flop with the...
This circuit was found in a Popular Electronics from the 90s. The counter circuit is not common...