I have a 12 VDC pump, 8.5A, connected to a MOSFET transistor PSMN5R6-100PS,127.
The connection from the transistor to transformer, pump and a ESP32:
1 Gate --> port to ESP32
2 Drain --> (-) pump
3 Source --> Gnd ESP32, (-) transformer
(+) transformer to (+) pump
This is, as I understand it, how it ought to work. But with this configuration it doesn't... But changing 3 Source --> (-) transformer, removing the Gnd connection to the ESP32, then it works. It, however, seems to be some kind of leakage in terms of current because the pump has a "clucking" sound, not fully activating, just making a sound. Sometimes it doesn't work at all, where a reset makes it work again. Any ideas how I can fix it reliably?