This continuity test was found in a 90s Electronic Engineering. Transistors are types of general use of the time with equivalents such as BC548 and BC558.
Only incandescent lamp can be used in this circuit. The SCR must be mounted on a heatsink and...
This circuit originally appeared in a publication of 1997. With the changes, the circuit can be...
This circuit is from a 1969 Electronics World. The transistors may be modern general-purpose...