Step 5: The Circuit
This is it! Not only is this the last thing you must BUILD, but it brings all the parts together (the coil, armature, and switch). The schematic is actually very simple. Follow the image notes. For the resistor, I said at the beginning that you would need to experiment. For testing purposes, start with 12 volts (12V) and a 1K ohm 1/4 watt resistor, then adjust resistor value and/or voltage after the motor runs if it runs too slow or the transistor gets too hot. Once you are done building the circuit, your motor is almost ready to run. More info in the next step.