Found in a 1964 Electronic Design this circuit compares two signals by providing the inverse of the algebraic sum of their frequencies. The circuit can be made with modern equivalent transistors.
This sinusoidal oscillator was found in Radio Electronics in 1989. It uses a 741, but other...
This is the circuit of a commercial flash from the 60’s. The circuit was published by the march...
This circuit is suggested by Motorola in its 1990 Linear Databook. The integrated circuit is no...