This circuit was found in a 1969 US documentation. It provides a signal that can be externally programmed as suggested circuits. The circuit can be used as a shield.
This traditional transistor source uses only two transistors found in a 1998 documentation. The...
In fact, it is a RF field indicator with an operational amplifier equivalent to the 741. This...
We found this circuit in a Motorola documentation from 1968. Phototransistors are common and...