How Does a Transistor Work?

How does a transistor work? Our lives depend on this device.

When I mentioned to people that I was doing a video on transistors, they would say "as in a transistor radio?" Yes! That's exactly what I mean, but it goes so much deeper than that. After the transistor was invented in 1947 one of the first available consumer technologies it was applied to was radios, so they could be made portable and higher quality. Hence the line in 'Brown-eyed Girl' - "going down to the old mine with a transistor radio."

But more important to our lives today, the transistor made possible the microcomputer revolution, and hence the Internet, and also TVs, mobile phones, fancy washing machines, dishwashers, calculators, satellites, projectors etc. etc. A transistor is based on semiconductor material, usually silicon, which is 'doped' with impurities to carefully change its electrical properties. These n and p-type semiconductors are then put together in different configurations to achieve a desired electrical result. And in the case of the transistor, this is to make a tiny electrical switch. These switches are then connected together to perform computations, store information, and basically make everything electrical work intelligently.

And thanks to Henry Reich and Vanessa Hill for reviews of earlier drafts of this video.

[kenj]

Video: "A problem we won't face until probably 10 years down the track."
Me: *Looks nervously at how old this video is now*

[mikecarroll]

In this 6 minute video, I learned more about transistors, and understood better how they work, than in a semester of my electronics class.

[andro]

I waited my whole life to see Derek dressed as a sillicon atom

[deawinter]

10 years down the track sure does feel a lot closer now. Maybe an update on this one?

[pushkarkhanal]

From 22nm 10 years ago when this video was made, to IBM's new 2nm chip, the fundamental principle is still simple yet groundbreaking.

[arthuranydonuts]

Almost 10 year update:

We essentially have 3 more years worth of improvements left. There are lots of improvement in terms of how power is delivered, changing shape of transistors (GAAFET) that will primarily give performance improvement.

The 3 year delay is also mainly because there has been slowdown in improvement in recent years.

After that, your galaxy phones and macbooks will essentially have same performance with every new release.

[mzshmkn]

This is basically my favorite video on explaining how transistors work. Especially as to how the electrons/holes flow in both on and off states. I've probably come back here at least once every semester when reviewing.

[aaronboonstra]

The first time I watch this video I had very little knowledge about electricity and semiconductors, but as I've taken more classes through college, , especially since I'm getting a materials science degree, I've learned so much about these topics and I've gone back to this video and I'm amazed by how much more I know about semiconductors and electricity now.

[mostafahesham]

"A problem we won't face until probably 10 years down the track."
well, we are in 2021 now so, we are facing this problem very soon

[jamesconnor]

I'm an engineering student, this is better explained here than in my classes haha it's impressive. Keep up the good work. Love the atom suit by the way.

[sundarpranesh]

1:04 I was searching the for the 4th electron, and he turned around . I just lost it 😂

[michaelwarnecke]

"But they are both neutral"
Adds switz plus-sign flag

[tonirazz]

Little mistake: By applying a gate voltage, you don't really encourage electrons to jump out of the Source region. You attract electrons from the substrate underneath the gate, and repel holes at the same time. And as soon as there are more electrons than holes, this region behaves like an n-type layer (this is called inversion), and that way, it connects Source to Drain.

[georgeti]

Great videos, as always. One correction for accuracy: While the focus appears to be on transistors in digital circuits, in reality, all transistors are much more than switches. They have a full range of operation between 0 or "OFF" and 1 or "ON". This continuous range is how common analog signals like audio, raw sensor voltages, or radio waves are amplified.

[ggwpBC]

2013: The current transistor size is 23nm
2021: IBM now working with 2nm chips

[planetarynebulae]

3:21 Ironic that the Swiss flag could be interpreted as a plus sign.

[kpiyer]

Loved it!! I am re-learning transistors after about 30 years! And I can see this is by far the BEST explanation I have seen/heard. Great job.. I am going to share it with many people!

[andrewdavies]

2013: "A problem we won't face until probably 10 years down the track.
2023: 👀

[ahmeterhanarik]

Do not ever delete or remove this video. So friggin helpful!!!

[Avionics]

The BEST transistor demo I have come across on the web. WELL DONE !!! and thank you.