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.
Found in American documentation from the 90s, this circuit uses TTL technology and is therefore...
Found in a 1968 Electronic Design, this circuit is intended for suppression of trigger noise in...
This amplifier for audio transmission lines was found in a 1961 American publication. The critical...