1 kHz low pass filter (CB7579E)

This filter can be implemented with almost any operational. The power suppply must be symmetrical.

Two Transistors MW Receiver (CB3976E)
This receiver was found in a 1968 publication, but can be mounted with a BC548 and BC558 in place...
Motor reversal with DC control (CB8952E)
Found in 1965s General Electric documentation, this circuit is intended for the control of servos...
Wireless Wiretapping LM302 (CB19323E)
The integrated circuit used in this 90's circuit is not very common today. An equivalent...