Why do Junction Transistors Amplify Current and not Voltage

Рет қаралды 6,455

Vocademy - Electronics Technology

Күн бұрын

It's about linearity.

Пікірлер: 15

@mohammadrezakarbasi1535 11 ай бұрын

Sir! I want to repeat this everyday: You are the best Electronics teacher in the whole world. Thank You very much!

@charlesschneiter5159 Жыл бұрын

Thanks for this latest refresher! You are a teacher of great talent 👍

@michaelmccarty4765 Жыл бұрын

Very, very helpful! I'm a vacuum tube guy trying to understand transistors, be them a BJT, FET, JFET, MOSFET... and the others. I've never heard BJTs described this way before. It's a lot of food for thought. Thank you!

@whatzause Жыл бұрын

I've done a lot of work in electrical circuits, but thanks to you, today I found out (basically) how an air-conditioner works! Very simply explained. Thanks!

@tvamos73 3 ай бұрын

My teacher told me that if I can imagine the BJT is a current controlled current source and MOSFET is a Voltage controlled resistor.

@flurng Ай бұрын

Another terrific explanation, Bob! Yet, if I may offer a different point of view, the way I always understood it, is that the base-emitter (input) current directly controls the collector-emitter (output) current. Thanks to Ohm's law, increasing base voltage causes a rise in base current, which in turn, raises collector current far higher. Finally, thanks again to Ohm's law, this rise in collector current causes a substantial drop in collector voltage. And, conversely, dropping base voltage would have the opposite effect on collector voltage! (P.S. - I should point out that this explanation applies specifically to common- emitter circuits!)

@LISANCACOM 6 ай бұрын

Thanks, really informative, clear and educative video.

@jnc5255 5 ай бұрын

Thank u sir for great explaination keep up the good job and godbless

@patricklanra3507 6 ай бұрын

A very informative video - Thanks Sir

@ChrisHalden007 Жыл бұрын

Great video. Thanks

@klmkt4339 3 ай бұрын

In the world we should value and look for linear relationship. What i learned from transistor

@Coolgiy67 9 ай бұрын

How does it actually amplify the current? Maybe you can use the hybrid pi model to explain ?

@mikesradiorepair 4 ай бұрын

This is probably a oversimplification but here goes. The collector has a voltage applied to it. The emitter in the video example is tied to ground. The collector to emitter basically looks like a infinite resistance with no base voltage. Applying a small voltage to the base allows current to flow through the collector to emitter. The higher the base voltage the higher the collector to emitter current. So in a nutshell, the small variable base voltage controls a large collector to emitter current. Mike KC3OSD

@flurng Ай бұрын

Not to get into the whole "Conventional current vs. Electron flow" debate, but the truth of the matter, is that electrons flow from negative to positive. So, with an NPN type transistor, as shown in the example, electrons actually flow IN to the emitter. From there, due to the atomic structure of the semiconductor layers, approximately 5% of those electrons flow OUT of the base, while the remaining 95% flow OUT of the collector. This proportion is maintained regardless of how many electrons (thus, how much "current") are actually flowing at any given time. As a result, a small change in the base current creates a much larger change in collector current, thereby amplifying the current.

@jonahansen 3 ай бұрын

Short answer: Because that's how they work. There is always a relationship between voltage and current, and the operation of a BJT is best characterized by the current relationship.