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 circuit shown in the figure can be used to detect the operation of infrared sources whose...
This circuit is from a factory manual from the 80s. The circuit can be implemented with more...
This circuit for the logic control of the 555 in a power supply was found in the October 1989...