This circuit was found in documentation from the 90s. The transistors can be general-purpose equivalents. The circuit has two versions, one that drives LEDs and another that drives a relay as a load.
This programmable sound circuit was found in the July 1978 issue of Radio Electronics magazine. It uses an...
The circuit shown simulates a programmable unijunction transistor (PUT). Transistors may be common...
This simple test lets you measure zener voltage. The power must be higher than the diode tested...