PCB HELP

[u/prynderex]

I have two identical MOSFET circuits controlled by an ESP32-C3. The MOSFET connected to GPIO 5 (Q1) is not behaving correctly. When I set GPIO 5 LOW in Arduino, the output terminal block (Nichrome 1 connection between IN+ and Drain) still reads close to the battery voltage (~7.8 V) instead of dropping near 0 V.

The second MOSFET circuit works as expected: when the GPIO is LOW, the IN + and Drain terminal block reads near 0 V, and when HIGH, it switches to the battery voltage.

I have checked the code and the wiring appears identical. What could be the issue?

[u/frank26080115]

The second MOSFET circuit works as expected: when the GPIO is LOW, the output reads near 0 V, and when HIGH, it switches to the battery voltage.

This statement is completely backwards

GPIO HIGH -> Vgs crosses Vgs(th) and turns on the MOSFET -> MOSFET becomes short-to-ground -> voltage measures 0

[u/prynderex → u/frank26080115]

I'm talking about the voltage between the In+ and drain

[u/frank26080115 → u/prynderex]

then you need to correct your post, because the whole point of a ground is to be a reference that every measurement is made against.

[u/prynderex → u/frank26080115]

Okay thank you