TTL Counter (CB21360E)

This counter from 0 to 9999 was found in English documentation. The power source must be 5V with at least 1A.

Fuel Low Warning (CB24111E)
This circuit was found in the April 1971 Radio Electronics magazine. It uses common transistors and can...
Telephone Scrambler (CB23524E)
This voice scrambler and descrambler circuit was found in a Radio Electronics from July 1963....
Ladder Generator (CB21245E)
Using a 4017 as a base, this circuit from a 1990s Popular Electronics generates low-frequency...