This circuit is from an August 1984 Radio Electronics magazine. It monitors the state of a RAM backup battery. Resistor R1 determines the battery charge.
This circuit is from an English magazine from 1976. By replacing the transistor for a BC548, the...
This diode tester was found in an English publication from the 1980s. Transistors are...
This circuit was obtained in a 1974 documentation. It shows how to use a JFET as a low intensity...