I'm trying drive a small DC motor (I want it to be adjustable but max it out at 1amp which happens around 2.2V) and I found this circuit online.http://www.elecfree.com/electronic/simple-miniature-motor-controller-by-lm317/
This was perfect for what I wanted to do....unfortunately it didn't work. Why is that? I tried two different motors i.e. a one inch long motor with the same diameter as a nickel and and a motor from a phone vibrator. I used a power supply and set it to 24 volts. For the big motor, it did nothing. The power supply showed it was pulling 40mA, and I think that's all from the LM317. The small one did a little better. When I turned the pot to 10k I got about a 0.2V drop, but that's it. I tried putting a small power resistor in line, I large regular resistor inline, and ditto for parallel (didn't think it would help but I just did it for good measure). Why doesn't it work?
I tried a transistor earlier but when I set it to 0.5 Amps it started to drift right away and at an exponential rate to max out the power supply (I melted a hole in my breadboard.)
I might have to resort to a PWM circuit using a 555 oscillator, but its so much more intensive to make rather than the LM317, a pot, a resistor, and a capacitor.
Thanks for any help.