EDN

Simple Siren Circuit

This circuit generates a tone that sounds very similar to a siren. The generator part of the circuit is made of the combination of PNP and NPN transistors. Toghether, the two transistors build up a ...
EDN

Cheap And Cheerful Transistor Tester

Alternatively, you may want to connect its inputs and output in parallel with IC1.C to increase its drive power to the transistor test circuit. IC1.A and IC1.B together with R2, R3 and C1 form an ...
Electronic Design

What’s the Difference Between PNP and NPN Transistors?

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 ...
Canadian Manufacturing

Key factors to consider when manufacturers are deciding between NPN and PNP transistors

Manufacturing companies, particularly those that mass-produce electronic circuits, work pretty much around bipolar junction transistors, like PNP and NPN. However, choosing between these two BJTs can ...
Hackaday

NPN transistors

[Dr. Cockroach]’s goal was to build a four-bit computer out of recycled and repurposed junk. The resulting computer, called IO, consists of a single 555, around 230 PNP and NPN transistors, 230 diodes ...