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.
In the figure we present an interesting application suggested by Microchip (www.microchip.com) in which the voltage...
This circuit was found in an English technical documentation from 1973. The circuit generates...
We found this circuit in a 1974 documentation. The NPN transistor can be the BD135 and the PNP the...