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I got this circuit that should drive electromagnet from ESP32 using 1RLZ44N MOSFET. I do think I got it correct but would appreciate feedback. I am a little bit uncertain on the placement of the 10 kΩ pull down resistor.

Here is my circuit:

enter image description here

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  • \$\begingroup\$ Please DO NOT update your question to correct errors I have already pointed out in my answer. \$\endgroup\$
    – Andy aka
    Commented Nov 11 at 11:11
  • \$\begingroup\$ You could replace advantageously D1 (too slow to dissipate energy - and is in the wrong direction) by a varistor across Q2. Choose a varistor voltage above 12V and well below 55V. \$\endgroup\$
    – user317139
    Commented Nov 11 at 22:18

1 Answer 1

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  • Your 1N4007 diode is connected the wrong way round
  • The 10 kΩ resistor is connected correctly
  • Make sure you don't get ground loops via and ESP32 circuitry
  • You should be OK with driving the IRLZ44N at 3.3 volt levels but, it really depends on your load current (less than 3 amps is my recommendation)
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  • \$\begingroup\$ ok. so now i updated my circuit. correct? You should be OK with driving the IRLZ44N at 3.3 volt levels but, it really depends on your load current (less than 3 amps is my recommendation) I might go above that for driving the electromagnet. Actually Im thinking of switching mosfet to for example IRLB8721 which has lower gate threshold voltage. Opinion? \$\endgroup\$
    – acroscene
    Commented Nov 11 at 11:22
  • \$\begingroup\$ Please provide a link to the MOSFET data sheet. \$\endgroup\$
    – Andy aka
    Commented Nov 11 at 11:26
  • \$\begingroup\$ here you go: https://www.infineon.com/dgdl/Infineon-IRLB8721-DataSheet-v01_01-EN.pdf?fileId=5546d462533600a40153566056732591 \$\endgroup\$
    – acroscene
    Commented Nov 11 at 11:44
  • \$\begingroup\$ I would say it is no better than 3 amps. You have to look at and understand figure 1 in the data sheet. It tells you that with a 3 to 3.5 volt gate drive nearly 1 watt will be dissipated for a 3 amp load. This is just a typical graph and some devices will be worse @acroscene \$\endgroup\$
    – Andy aka
    Commented Nov 11 at 12:23
  • \$\begingroup\$ @acroscene if we are done here, please take note of this: What should I do when someone answers my question. If you are still confused about something then leave a comment to request further clarification. \$\endgroup\$
    – Andy aka
    Commented Nov 27 at 8:32

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