This circuit keeps a set of lamps permanently on, even when there is a power cut. The circuit can be adapted to use LEDs and the 12 V battery can also be changed according to the lamps or LEDs.
This stage was used in old audio ampliiers and radios from the 1950s and 1960s. It uses one of the...
Found in a 90s R-E Experimenter Handbook, this amplifier uses an integrated circuit from that...
We find this circuit in an American 1980s documentation. The unijunction transistor may be the...