Found in a Popular Electronics from the 1990s, this circuit monitors the voltage of a power supply or battery. The trigger voltage is adjusted with a potentiometer.
This simple musical instrument was obtained from a 1967 magazine. If the original transistors are...
The transistor of this circuit can be the BC558. The circuit is from an old documentation...
We found this circuit in an old American documentation for hams. The circuit serves as a telegraph...