Question about driving a DC motor (current amplifying)

Thread Starter


Joined Jul 6, 2016
So I'm using an arduino, but I want to drive more current through the motors, so that they can go faster. Imagine that bipolar source to be the arduino.

So, imagining I have 4.7uA (Ib) at the output of arduino Ic would be 100*Ib (470uA), right? Another disclaimer is, ignore the phase, I know it would be off by 180 degrees, so I would need another transistor. So, if it was low, I would get 10V, if it was high, I would get 1k*100*Ib? If I wanted that to be zero, I would calculate the value of R1 by doing this operation 10/(100*Ib). Multisim doesn't seem to be giving me clear answers, and I've search for answers online and I couldn't get if I'm right or not. Also, if the resistor was low, I wouldn't get 0V, would it be possible to get 5V ( just an example) ?

Thanks in advance.
Last edited:


Joined Mar 10, 2018
You can't drive a voltage source into EB junction of a transistor otherwise
think about frying eggs on the part.

Here is an excellent low cost driver to consider, assuming your motors "smallish"

LM298 driver board.
Up to 2-3A kinds of current depending on Vsupply. Direct interface
to Arduino, L

Regards, Dana.