Using the 2N2646 this circuit was found in a Radio Electronics magazine from July 1968. The transistors are from the time and the lamp can be replaced by a high-power LED in a current version.
We found this circuit in an English publication from the 1980s. The circuit uses current...
This circuit uses common transistors for a fault indicator that turns on an LED and provides an...
This high current switching stage was found in a 1967 EEE. The power transistor is from that time....