Hi, I've been trying to vary a motor's speed with just a potentiometer but have so far had little luck. What I've tried is putting the full battery voltage across the entire potentiometer, then attaching my motor from the wiper pin to ground (see attached). It seems that no matter what the battery voltage, potentiometer value, or motor that I use are, I get no motion for most of the range of the pot, then a very steep ascent to full motion at the end. I've also tried it with a small incandescent bulb and gotten the same thing. The problem shouldn't be that the battery is maxing out on current draw, since I've tried reasonably large (10k, 50k, 100k) potentiometers (and gotten the same result for all of them).
One time I tried it with a 9V battery and an LED (I know that's not a safe voltage for most LEDs, but I wanted to see what would happen) and I did get the desired effect.
My physics knowledge tells me that voltage across and hence power delivered to the motor should be linear with my linear pot. So what gives? I know I could use an IC solution, but this has gotten me wondering what's going on...
One time I tried it with a 9V battery and an LED (I know that's not a safe voltage for most LEDs, but I wanted to see what would happen) and I did get the desired effect.
My physics knowledge tells me that voltage across and hence power delivered to the motor should be linear with my linear pot. So what gives? I know I could use an IC solution, but this has gotten me wondering what's going on...