This simple circuit has helped me out on many occasions. It is able to check transistors, in the circuit, down to 40 ohms across the collector-base or base-emitter junctions. It can also check the ...

In the early days, PNP bipolar transistors were common, but the bulk of circuits you see today use NPN transistors. As [Aaron Danner] points out, many people think PNP transistors are “backward” but ...

A previous Design Idea describes a circuit that uses an astable multivibrator to drive an LED (Reference 1). The circuit in Figure 1 uses a simpler alternative approach. The circuit uses a 2N3904 NPN ...

The transistor is probably the most important invention in electronic engineering and the basis for nearly all integrated circuits (ICs). The transistor is a three-terminal electronic device that can ...