Hello everyone I'm doing my project controlling three water mini pump by one board with transistors BC337. The pin will give power when touch sensor sensed something which is embedded in the esp32. The code is right, but the physical part made me confused.
The issue is when I use a breadboard, everything works well, but after I solder them, there is always one pump or two pumps on without any control signal,
you can see the circuit in the figure, the base resistor is 3k instead of 220, I also tried 5k resistor but same issue.
I desolder and solder several times, the same way or different way, with or without experiment board, but the issue is same. I checked the transistors, they are fine. I also tested all pumps one by one in the same circuit, it works well, but after soldering them together, issue happens again.
more details about Pins and components:
Pins: 26&27&16, can't show right on in the figure
Water pump works in: 3-6v, 100-200mA
NPN transistor: BC337 datasheet: https://www.onsemi.com/pdf/datasheet/bc337-d.pdf
[btw I also tried 2N2222 same issue.... my god]
ESP32 wemos D1 R32 : https://www.otronic.nl/a-60659537/esp32/wemos-d1-r32-esp32-4mb-development-board-wifi-bluetooth-dual-core-arduino-uno-r3-formaat/
I assume something wrong with the circuit, so when I solder/combine all pumps together, maybe the power value has been influenced then the current has increased even no signal from the base that open the NPN?
I will appreciate if you can help with this weird situation!