This circuit was found in a 90s Popular Electronics. The circuit uses 4 bicolor LEDs to indicate signals of both TTL and CMOS logic. The circuit is powered by the source of the circuit under test.
This circuit is from a 1967 General Electric SCR manual. The capacitors are polyester and the...
This oscillator for frequencies up to a few tens of kilohertz was found in a 1970s documentation. The...
This varicap-less modulator circuit was found in an Electronic Design from the 90's. The circuit...