I have found many YouTube videos explaining MOSFETS and transistors, but I still do not understand what exactly they do, and how to use them. Could someone please explain what you use them for and how to use them in a practical circuit?

 

Don't know if this would work for you, but this type of understanding helped me long ago..
https://en.wikipedia.org/wiki/Hydraulic_analogy

 

Transistors and mosfets allow you to use a small voltage or current to create or control (depending on how you look at it) a larger current flow which is very much proportional to the controlling voltage or current. This larger current can be seen as a lower impedance supply or a larger voltage depending on how you want to use it. This is how we get from tiny signals like a microphone, to a thousand watt speaker system. (But it takes more than one stage to do that job.)

 

I have found many YouTube videos

Perhaps that is your problem. Try reading a book written by someone with actual knowledge and teaching skills instead of relying on random people’s videos which may be entirely incorrect.

If you want help here, try to tell us what you think you understand, and what questions you still have.

Bob

 

 

Transistors and mosfets allow you to use a small voltage or current to create or control (depending on how you look at it) a larger current flow which is very much proportional to the controlling voltage or current. This larger current can be seen as a lower impedance supply or a larger voltage depending on how you want to use it. This is how we get from tiny signals like a microphone, to a thousand watt speaker system. (But it takes more than one stage to do that job.)

Good definition. I HATE the word amplifier. It is so misleading. The transistor or mosfet controls. Amplifies sounds like it is doing something magical (not that electronics isn't magical ).

 

.LEDs, 555s, Flashers, and Light Chasers
look at chapter 10

 

Thanks. This has been helpful. I now have more of an idea of what they do. Just wondering, could you make a DC to (sinusoidal) AC inverter with just basic components like transistors, capacitors, resistors, that kind of stuff, or do you need complicated ICs? If you can, how would you go about doing it, and could you adjust the frequency by changing component values?

 

You can make a very simple inverter that can power incandescent light bulbs and a heater. A more complicated inverter can be made to power electronic products.
Usually an inverter has its frequency fixed to the frequency of the electricity in its country, but a switch can change the frequency if you want.

 

Wendy's Index

AC/DC Inverters

 

I like helping people design things But I would be the first to say off the shelf device are more likely to cost less and have fewer unpleasant surprises.