I have a question about powering my 3-6v DC motor. When it’s plugged into the 5v or 3.3v supply on my Arduino, it works fine. If I connect it directly to a 9v battery, it works fine. However, when I try and make a voltage divider from a 9 or 12 volt supply, the motor will not turn at all.
I’m more or less a complete beginner and feel like I’m probably making a schoolboy error, but I just can’t figure out the problem. I’ve checked the voltage available across the voltage divider and can successfully create 3 or 6 volts from a 9v battery and 6 or 9 volts from a 12v battery, however when I connect the motor it does nothing. I’ve tried using different resistors (10k & 20k; 2k & 1k, 200r & 100r) and still no joy. I’ve tried the same circuit but just using 2 LEDs in series (~6v consumption) and it works fine.
Essentially, 9 volts directly from a battery (or 3.3 or 5v from Arduino) spins the motor, however 9 or 6 volts from a divider does nothing. I’ve spent a long time now just doing sanity checks and getting nowhere, it’s driving me crazy.
I'm not sure what this means or if it helps but I'm getting a reading of either 0.00 or 0.02 volts on the multimeter, when measuring across the motor. If I replace the motor with 2 LEDs in series, when taking a reading from the same point I get 5.90 volts.
Any help would be greatly appreciated.
Thanks in advance!