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.
Found in a 90’s American publication, this circuit has a voltage gain close to 1, as shown in the...
Using a pair of 741 op amps, this 90 s Radio Electronics circuit works with the previous one. The...
This circuit is from a 1966 Motorola Field Effect Transistors Manual. The circuit makes use of...