This circuit for a digital module was found in the September 1989 Radio Electronics magazine. The source must be symmetrical to the operational amplifier.
We obtained this circuit in a Maxim documentation from the 90s. The circuit is based on the...
This circuit was found in a 1965 General Electric publication. The circuit can be adapted to...
Based on Radio Shack 276-137, this circuit was found in the December 1995 issue of Electronics Now magazine....