This 1968 Mallory circuit uses an uncommon integrated circuit today. The circuit has a 30 to 20,000 Hz response with lower power and is powered by 12 V.
Found in a November 1977 Radio Electronics magazine, this digital circuit was described in an...
This circuit is from a manual of linear integrated circuits of the 80s. The operational is of the...
The tone generated by this bell changes when we press and release the switch. The circuit is from...