How many remote controls do you have in your home? Don’t you wish all these things were better integrated somehow, or that you could add remote control functionality to a random device? It’s a common ...

A simple and convenient way to interface 2 relays for switching application in your project. This relay driver boosts the input impedance with a regular BC547 NPN transistor (or equivalent). Very ...

Fig. 1: Add this relay to prevent shorted transistors in the MW-1. Usually after a transmitter is discontinued, any hope of upgrades or improvements fades. Some enterprising engineers can’t help but ...

The two types of standard transistors are PNP and NPN which differs in circuit symbols. The layers of semiconductor material used to make the transistor are denoted by the letters. To keep a straight ...

Relays usually are driven using optocouplers, which offer isolation between analog and digital grounds to ensure that switching currents in the relay coils do not affect the noise margin of 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 teacher I know is stuck, with only npn transistors in the supply cupboard and the need to create a reversible motor drive for an Arduino project. Reversing ‘bridges’ have four switches (relay ...

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 ...

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 ...