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.
This siren circuit was found in a Popular Electronics from March/April 1969. We can easily...
This power stage with two counterphase transistors and coupling transformers was shown in Radio...
This circuit is a sample of a DC amplifier used in the 50's. The transistor is germanium and very...