This 1950s audio amplifier uses output tubes of type 1625 in its output stage. The Class B circuit provides a few watts of power and uses transformers that are not readily available today.
In the original publication of the 90s a 556 consisting of a double 555 is suggested. The circuit...
This circuit was found in a 1966 EEE. The circuit uses transistors from the time but can be made...
This circuit can be used in alarms by activating a relay or a current load that depends on the...