This simple logic test circuit with 3 LEDs was found in October 1985 Radio Electronics magazine. The power supply is according to the logic, and this version is indicated for TTL.
The transistors of this circuit may be general purpose and the power supply comes from the TTL...
We found this circuit with the CMOS4046 in the August 1994 Electronics Now magazine. The circuit is...
This setting appears with variations at various points on this site. This is from a Motorola...