I’m working on a project to automatically water my plants. Pretty standard.
But, I’m having some serious trouble getting the circuit to work. I think it’s a problem with my transistor (or my understanding of it). I attached a image of the circuit and the transistor. The solenoid valve is powered by a 12V, 800mA, unregulated wall wart. The 0/5V signal for the base of the transistor comes from the Arduino Uno.
My problem is that I can’t seem to “close” (open circuit). Even when the transistor should leave the gate closed (open circuit), it is allowing 600mA to get through from the emitter to the collector. Additionally, the transistor is getting ridiculously hot and melting my wires.
I know I have the control of the transistor right, because I can run the program no problem when I only use an LED off of 5V instead of the valve and the power supply. I think it may be some form of incompatibility between the Arduino Uno, the transistor, and the power supply.