i used this as a base for a project that i am doing, i have now copied this exactly, without the pot.
Instead of getting lots of extra power, im only getting about .2 volts to the motor.
I tested the voltage at at the collector, its 6v*, when no power is sent to the base, 0.9v when power is applied to the base.
I tested the voltage at at the Emitter, its 0v when no power is sent to the base, 0.1v-0.2v when power is applied to the base.
I am using exactly what they say here, the tip120, (i have tried about 5 tip120s, so i doubt its a fault with it)
I also noticed that when i share the grounds, i can no long upload to my arduino (uno)
*or 7.4v if i turn up the wall wart, just confirming power is comming from the wart.
Anyone got any ideas, cause i am stumpped.
Well, it seems that although the readings are wrong, i do seem to actually be getting higher voltages, anyone know why its not reading correct. or why you cant upload with shared grounds.