ESP8266 Community Forum

Hi everybody. When I connected ESP GPIO0 -> 1K -> BC237 (NPN) transistor Base -> Relay I can't control the relay. But I connected ESP GPIO0 -> LED (Serial "+ Connected GPIO 0 and - Connected Transistor") -> BC237 (NPN) transistor Base -> Relay it is working very good. I can't understand this problem. I tried pull down GPIO0 with 10K resistor but the result same. I am writing code with arduino ide. I set GPIO0 as output. Thank you.

This is a forum about electronics and programming, not crystal ball readers unlimited: please show us some code and an actual schematic.

If you reset / start esp with gpio0 pulled low (via direct resistor or resistor and be path of transistor) it will not start your sketch.