What is a transistor? How does a transistor work? Part 2

This video describes how a transistor is used in simple and more complex circuits. Tip jar: http://bit.ly/icYMcw Thanks!

Category:

Education

Tags:

• transistor
• transistors
• work
• works
• simple
• simplified
• basic
• electronics
• opamp
• amp
• amplifier
• beginner
• beginners
• dummies

[chancerogers85]

@SteelWheelsDown So basically a transistor is kind of like a varying NOT gate? if the input is low then the output is high.

[SteelWheelsDown]

A transistor (bipolar junction) is a variable resistor whose collector-emitter resistance value goes down as the base signal goes up. In a voltage divider where the transistor is on the bottom, yes, the output of the divider will be inverted, and it can only sink current. If the transistor is on the top, the divider output is just a buffer, and it can only source current. To both source and sink, the divider can have transistors in both top and bottom (TTL, or complemetary push-pull setup).

[mbsfaridi]

So how do microprocessors calculate and do other stuff by just transistors resistance changing?

[SteelWheelsDown]

@mbsfaridi, transistors are at the heart of microprocessors. Transistors are used to construct logic gates (AND, NAND, OR, NOR, NOT, etc.), and logic gates are put together to create larger circuits like flip-flops (bi-stable multivibrators, capable of "storing" a value until its input changes). If you give each "bit" its own flip-flop, you can string 32 of them together and get a CPU register. Digital counters, shift registers, binary adders - put all of that into a chip, and that's a CPU!

[GraysonDean1990]

you are as passionate as my Russian professor, but only 10 times better....:)

[Minnie1799]

BRILLIANT!! THANK U SO MUCH!!!

[drmns]

Great videos. keep it up.

[meholah]

what a fantastic explanation. the parallel between the basic amplifier circuit and a voltage divider gave me a stronger fundamental understanding of the operational range of a transistor. ty!

[123arskas]

You are my Teacher !!!!!!! I Love your Simple Explanations. Albert Einstein also liked to explain things in a simple manner !!!!

[SteelWheelsDown]

@Sekuhara, it is certainly possible to do that. In fact, in most circuit outputs, especially for logic and computer chips, there is a transistor in both the top segment AND the bottom segment. These two transistors act as a pair, and complement each other, so that as the lower transistor conducts, the upper one does not, and vice versa. This is why they call them CMOS chips - Complemetary Metal Oxide Semiconductors, a complement pair of MOS transistors making the output stage.

[Sekuhara]

Just one question regarding the transistor inverting the signal: wouldn't it be possible to just put the transistor in the top segment of the voltage divider and a conventional resistor at the bottom? Low input voltage would cause output to align to 0, and the high input - to Vcc?

[Sekuhara]

First of all - amazing explanation! I truly felt enlightened after watching this.

Previously, my knowledge of electronics never got further than the simple DC circuits with resistors only (Kirchoff's law, etc). Capacitors, inductances and semiconductors always seemed black magic to me. Now that I know that the transistors are used just as a special kind of variable resistors, and capacitors as plugs to prevent direct currents flowing to other segments, I feel much safer in this deadly domain :)

[Phrazemaster]

Wow! I can't imagine a better explanation! Thank-you so much! Just like you said I had been trolling the internet and youtube trying to understand the transistor, but you turned on the lights for me in a HUGE way! You sir, are a brilliant and gifted teacher!! Thank-you!!!

[praveensmile99]

sir ,u r the one who explained about the transistor a lot in a quite short time.

please explain us the mechanism inside it.i mean how a transistor can produce required resistance for respective input signal.can u tell me which book is better for electronic devices and circuits.

once again thank u very much ......sir(awaiting for ur reply)