Logic level indicator 7400 (CB22407E)

In the figure we have a simple logic level indicator for TTL circuits or powered by 5 V.

Electronic Ignition RCA (CB4623E)
This circuit is suggested by RCA and is based on a dedicated integrated circuit that is the...
JFET VCO (CB21133E)
This circuit was found in a Popular Electronics from the 90's. The frequencies depend on the...
NAND Gate with 1 Transistor II (CB19883E)
We show in the figure how to implement the No-AND or NAND logic function using a general-purpose transistor....