I was hoping someone could help me out with a problem. I have a 4.5 volt 100 ma max DC motor and wanted to use my 9 volt DC 1700 ma power supply to power it. I thought that I could use a resistor to bring the voltage from 9 down to 4.5 volts DC. I've read there might be an issue with the current and it could burn out the motor, so a current limiter is needed. When I use this motor, I'll be using it 10 seconds at a time so it won't be constantly running. Do I actually need a limiter? If I do I don't know which component values to use for my specific set up.