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.
The purpose of this project is to monitor remote loads. The windings are made in a burnt...
The scale of this scale uses LEDs, and its accuracy depends on the number of LEDs. We found this...
We find this circuit in an American documentation from the 80's. The circuit has the coil given by the...