Will this H-Bridge work?

Projects General Guidance
1

Hello,

I'm trying to invert an Electromagnet and didn't had an H-Bridge IC. I planned a circuit with
N-Chanel Mosfets(https://www.infineon.com/assets/row/public/documents/24/49/infineon-irlb8748-datasheet-en.pdf?fileId=5546d462533600a401535660665b2595) and don't know if it will work or if I done something false.
Below is the circuit.
Thanks for your response

Bildschirmfoto_20260309_144454
Bildschirmfoto_20260309_1444542816×1548 122 KB

2

It won't work like that. To use N channel mosfets on the high side you need a special driver to lift the gates above the 6v rail.
Look for a design with P Channel mosfets on the the high side or look for a ready made H-Bridge board.

This may help: https://www.allaboutcircuits.com/technical-articles/h-bridge-dc-motor-control-complementary-pulse-width-modulation-pwm-shoot-through-dead-time-pwm/

3

OK thanks!
Would it work if I use a voltage below 5V for the Electromagnet?

4

Again, No. For an explanation, scroll to the last design in this link which shows a circuit with 4 N-channel mosfets entitled "Faulty Bridge" :

Incidentally, some of the circuits and information there may be appropriate for your application.

1 Like
5

thank you!

6

How much current does the elecromagnet need?

7

0,375 Ampere

8

If you don't need to switch back and forth very fast you could just use two SPDT relays.

2 Likes
9

I think that won't work, because it needs to be quiet.

10

375mA is not much current so you could use tiny relays that just barely make a small click noise if you put your ear right next to it but it's up to you.

11

Thanks, but isn't there something I need to change so it will work because I already have these Mosfets at home or won't it work because of how Mosfets work?

12

@6v6gt has allready explained it won't work and to make it work you would need to buy additional components.

1 Like
13

Give the solution to @6v6gt, I just repeated what he said.

14

but also thanks jim-p

15

You are welcome

16

Much easier and cheaper to buy a DRV8833 or TB6612 H-bridge.
Leo..

17

So what do you plan to do?

18

I planned to build a fake perpetuum mobile in form of a piston. I want to have a electromagnet to push and pull on a Neodymium magnet, so the piston moves.

19

I meant regarding the H bridge. Will you buy an off-the shelf module or still try to build your own?

20

I will by a IC or a relay. When I’m finished I try to build one myself. I think so.