This circuit was found in a 1964 Electronic Design. The transistor may be a current equivalent of general use. The frequency ranges from 100 to 150 Hz.
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...