Hi, I have mastered almost all electronic components that I have come across except the transistor. Will someone please send me a simple circuit that uses a transistor with a brief explanation of why it work and what it does? Thank you, Jared Adams

I have mastered almost all electronic components except the transistor

This reminds me of when I was 9 at school. I thought I had mastered all of math, where as I had mastered all the math I have ever come across, a totally different thing. So you are OK with the unijunction, the triac, the SCR, the veristor, the quantum tunneling diode, the varicap and FPGA?

Well make a start on transistors here:-

I have mastered almost all electronic components except the transistor.

Way to go, after 30 years I still can’t say that, but then I’m a slow learner :slight_smile:


42 years for me... and I can't say it either.

Now, now, folks… play nice! <^_^>. At least add some information to the leg pulling!

With the Arduino, transistors seem to be used most often to do the job that might be done with a relay, although a relay can’t switch on and off as fast as a transistor can, and that is an issue in some applications, e.g. producong an audio tone. Both can be used to “switch things on and off”.

The Arduino can’t “switch” a big current, or a voltage of more than 5v (or 3v3 if you’re using a 3v3 Arduino)

Sometimes, if the current or voltage is large, and the switching not rapid, a relay is a better “switch”… and relays are more beginner friendly, as long as you include The Diode…

When I was an apprentice (some 50 years ago) one of the favourite tradesmen sayings was "Son, I've forgotten more than you'll ever learn"

It took me a long time to appreciate what they meant and I too am of the opinion that today's "oldies" have probably forgotten more than today's youngsters will ever learn - and if the truth be known, we're still learning - but that might be because we've already forgotten it.

Yes, technology has advanced immensely but regrettably many true craft-skills have been lost, probably forever.

It makes one wonder how massive buildings were erected and empires created with "primitive" technology, slow communication, lack of transport etc

Have a look at:,81011.msg611756.html

it finally makes some sense.

tkbyd: [sic] although a relay can't switch on and off as fast as a transistor can [...]

Well, can't agree on this one... what about SSR's ? :D


A Solid State Relay is a (packaged) transistor!