Found in the October 1979 Radio Electronics magazine, the purpose of this circuit is to monitor the coolant level in a car's radiator. The circuit is based on the LM1830.
Suggested by Fairchild in a 1980s publication, this multiplier uses operational amplifiers from that...
This circuit, from a 1981 publication, can be changed to use more modern components such as the...
We find this circuit in an American publication of 1978. The integrated circuit is the CMOS 4013...