Found in an 1868 Mullard documentation this circuit has a dynamic range of 10 Hz to 25,000 Hz. Modern equivalent transistors can be used.
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...