This circuit was found in a Popular Electronics from the 90's. The operating curve is given next to the diagram. The power transistor must have a heat sink.
This circuit sounds when the input voltage drops below the value determined by the zener. The...
This simple test tells you whether a PNP or NPN transistor is OK. The signal is given by turning on...
This circuit generates a precise 100 kHz signal. The signal is given by a crystal and can be used...