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New to electronic circuits design. I have this MP3 player connected to ESP32, I want to turn it on and off using a N-channel MOSFET, where it turns on when sending high signal and off when sending low signal. An engineer told me to connect the drain to ground like below. Is this right? How is this going to turn the MP3 player on and off?

  • \$\begingroup\$ That connection doesn't seem right. The transistor is connected to GND on both source and drain, so there's nothing that it's really controlling. Were you looking for something more like this article's schematics, perhaps? \$\endgroup\$
    – nanofarad
    Nov 11, 2023 at 21:33
  • \$\begingroup\$ I know right! the drain should be connected to MP3 Vcc pin, it's pulled down by the resistor so it's off till I send a signal to the gate, Am I getting it right? \$\endgroup\$ Nov 11, 2023 at 21:42
  • \$\begingroup\$ please stop shouting. \$\endgroup\$
    – Hearth
    Nov 11, 2023 at 22:44
  • \$\begingroup\$ @AlAnoodBallan If you're using an nFET as a switch, it needs to switch the low side of the load \$\endgroup\$
    – nanofarad
    Nov 12, 2023 at 1:21

1 Answer 1


What the "Engineer" and the other comments are trying to convey is that you break the ground connection (or the - power connection) on the MP3 system and replace it with the N-channel MOSFET. Connect the MOSFET Drain pin to the open MP3 system's ground connections, then connect the MOSFET's Source pin to the original ground (or - power connection). The ground of your controlling circuit also needs to be connected to the original ground (or - power) connection. See diagram below.

(Also be sure that there are no other ground connection to the MP3 system, if there are group them with the MP3 pins on the MOSFET Drain.)


simulate this circuit – Schematic created using CircuitLab


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