View Full Version : 2 questions

08-03-2005, 04:18 AM
hi guys,
i have two newbie questions:
1. i have some motor salvaged from old walkman, it works on 3.4V, having it secured with diodes, connect it directly to a microcontroller since it's operating voltage is less than digital logic voltage???
2. i also salvaged a motor from a CD-ROM (not a stepper, but a small DC motor) how can i see what it's working voltage is if nothing is labeled on it? it is rather small, so i guess it works on less voltage than above mentioned one.


08-03-2005, 06:46 AM
well don't connect motor directly to uC...

uC can't source/sink currents more than a few millamps (10-20) and thats insufficient to run the motor...secondly if the motor forces the uC to source more current due to its low impedance...the uC port may get damaged...

08-04-2005, 08:59 AM
oh, i see

09-10-2011, 07:41 PM
motor from a CD-ROM -5v and i agree with maxasimo
use l293D for interfacing

05-05-2016, 04:58 PM
Maxasimo is right!! Donot connect the motor directly to the UC.