How to power MOSFETS

Thread Starter

Sulvek

Joined Aug 27, 2022
25
Hello all. I just purchased a collection of MOSFETS to learn about them. As seen in the pictures 1 of them even goes up to 400v. What is the easiest way to power these? I have transformers of all types of values but I was looking for a variable power supply that can go from 100v-500v. My bench power supply only goes up to 30v. Any advice on this is a huge help. Thanks guys.
 

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MaxHeadRoom

Joined Jul 18, 2013
28,827
You don't really need a supply of 500v for learning purposes, unless you have an actual application where it is needed.
400v versions will work at a lot less !
 

WBahn

Joined Mar 31, 2012
30,298
What do you mean by "powering a MOSFET"?

Do you think that if a MOSFET is rated for 400 V that you need to "power" it with 400 V to get it to work?

If that is anywhere close to what you are thinking, you need to stop before you go any further and learn a bunch of basics. If you start playing around with supplies that go to hundreds of volts, you are likely to find that they can push lethal currents through you the hard way.
 

BobTPH

Joined Jun 5, 2013
9,272
WBahn wrote pretty much what I was going to write.

These MOSFETs will require 10V at the gate to turn fully on. You don’t need any voltage higher than that to learn how they work.

The voltage rating is the max voltage you can place across the drain and source without damaging them.
 

MaxHeadRoom

Joined Jul 18, 2013
28,827
@Sulvek look up the design application notes on Mosfets on the International Rectifier site, Designing_with_power_MOSFETs-ApplicationNotes-v01_02-EN.pdf etc.
They have very in depth explanations on usage.
I believe they are also now Infineon
 

Thread Starter

Sulvek

Joined Aug 27, 2022
25
What do you mean by "powering a MOSFET"?

Do you think that if a MOSFET is rated for 400 V that you need to "power" it with 400 V to get it to work?

If that is anywhere close to what you are thinking, you need to stop before you go any further and learn a bunch of basics. If you start playing around with supplies that go to hundreds of volts, you are likely to find that they can push lethal currents through you the hard way.
Oh okay so the 400v for instance is just the max voltage that can flow through it once on but to turn on it may need only 5v or some other low voltage supplied to it? Good morning by the way and thanks for the reply.
 

BobTPH

Joined Jun 5, 2013
9,272
Voltage does not flow. And, if the MOSFET has 400V across it when it is on, it has already gone up in smoke. The voltage across it when on is usually a fraction of a volt.

The voltage rating is the max voltage across it when it is off, not on.
 

Jerry-Hat-Trick

Joined Aug 31, 2022
588
My bench power supply only goes up to 30v
30 Volts DC is pretty safe and mosts projects and ideas can be built or tested at that or a lower voltage. Even at low voltages it's a good habit not to touch anything whilst power is connected, and make sure capacitors are discharged even after power is removed. I seriously recommend not using any higher voltage until you have experience and even then, never without someone nearby to help if you make a mistake.
 

MisterBill2

Joined Jan 23, 2018
19,424
You can learn the use of mosfet transistors with a supply for the drain voltage and a resistor, and a variable source to supply a gate to source voltage. Then you can vary the gate to source voltage and monitor the drop across the drain resistor.
But even better is reading the application notes and the application guides.You can also learn what that operation voltage specification means.It IS IMPORTANT!!
 
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