We found this circuit in a 1969 General Electric documentation. The circuit uses transistors of the time and the diodes in the dotted board must be mounted on the output transistor heatsinks.
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...