How To Build Reliable, Powerful, And Inexpensive Voltage Drops, Part 1: Resistors - When Less Is More Photo Gallery
Devices like motors seldom indicate their current draw but we can measure it using a multi-tester. Set the tester to its current-sensing setting and wire it between the device and a power source that matches the device's voltage. A resistor would knock 24 V down to 12 V for this motor, but being a 4-ohm, 25-watt monster would make it impractically large and hot. This would be a candidate for a voltage drop we'll build next month.