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I have two older MRC Tech II model 1500 DC controllers that I want to use to power my DC accessories, like Tortoise switch machines and the motor drive for my Atlas turntable. However, the Tech II puts out 20v fixed DC, and I need to drop that down to 12v (the turntable motor 'races' with the full output). Anyone know what size resistor I need to put in series with the output to drop the voltage from 20v to 12v? I did a search on resistor calculators in Google, but the vast majority I found are for figuring out the value of a resistor from the color bands, or for figuring out the size resistor needed for an LED, neither of which particularly help me. [banghead] I did find one that calculates voltage divider circuits, but that's not quite what I'm doing either. So if you could suggest a resistor I should use, or point me in the direction of a calculator that'll figure out the resistor needed for a particular voltage drop, I'd appreciate it. Oh, and Happy Holidays, one and all!
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