This simple logic level tester was found in Radio Electronics from the 90s. The inverters are of the 4009 type and the power comes from the circuit being analyzed.
This circuit, found in a 1964 US documentation, consists of a selective amplifier that lets only...
This circuit serves as a reference for the components used and the time. The circuit is from 1967...
This stereo circuit with the 2002 integrated circuit. The power is 6 W per channel with 16 V of...