We found this precision circuit in a manual from the 80's. The operational amplifier is of a common type at the time, and equivalents can be tested. Transistors are general purpose types.
This circuit was found in a 1992 publication. What it does is to light an external lamp when it...
This circuit can monitor direct or alternating currents. Resistor R1 is calculated so that the...
We found this multiple thermostat circuit in July 1980 Radio Electronics magazine. It uses...