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 power supply with several transistors can supply a current of several amps and a voltage of...
Found in a 1967 EEE, this circuit oscillates at 20 MHz according to the values of the given...
We found this circuit in a 1974 technical documentation. The circuit can be made with BC549...