This 1969 Mullar circuit appears elsewhere on this site. The circuit uses germanium diodes and the indicator is microammeter with zero in the center of the scale.
Suggested by Fairchild in a 1980s publication, this multiplier uses operational amplifiers from that...
We found this circuit in an English publication from 1980. It provides a logical output signal when...
This unusual amplifier configuration is from 1986. The circuit has a high resting current given the...