I have this very basic circuit featuring:
- 12V LED strip
- N-Channel Mosfet BUZ 11
- 12V Power supply
- NodeMCU (ESP8266 wifi dev. board)
I'm trying to use the NodeMCU for dimming or simply turning off the LED strip.
But as soon as I use a different 12V power supply (I have tested 3, from old routers and other devices), it doesn't work anymore. The LED usually stays on but on one other power supply it always flickers.
Even more strange the negative pin of the power supplies sometimes seem to work as the gate pin of the MOSFET as when I touch it without a resistor, the light flickers or turns off.
I have tested:
- 3 different power supplies, it only works on my lab bench power supply
- 3 different NodeMCU controllers (just in case)
- With or without the 10kΩ resistor between the NodeMCU and the Gate
- Changing all cables I used
- Using a 12V voltage regulator before the MOSFET
- Using different MOSFETs (2N7002, IRFZ24NPBF, BS170, BUZ11)
I'm fairly new to electronics as I've always been a "software guy" so it could be that I'm missing something very basic here.