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Topic: Problem with dc motor (Read 902 times) previous topic - next topic

serbar

Hello.

I am newbie, i am trying to put a small dc motor working and regulate speed with PWM generated by arduino. The transistor i am using is a bc547c.

The problem is that the motor make a strange noise but doesn t spin (no its not damaged). Connected an amp to see the colector current and it increases as i increase duty cycle, but the voltage between colector and emiter stays more or less the same. Shouldn t that decrease as current increase? There is no voltage across the motor as it stays in the transistor.

Motor is a mabuchi from a car toy;

As external motor source i used 4 1,5 V batteries;

I calculated resistor base to have enough current to feed the motor according to transistor and motor datasheets.

Do you have any idea for wath is happening?

Thanks.

zachwiej

Try wider pwm pulse(analogWrite() 100-250 )  or maybe try more powerfull transistor

serbar

Thanks for reply.

Already tried TIP31C that is a power amplifier transistor. By the way it was the first i tried, before bc547c. It does exactly the same, What do you mean aboute wider PWM? Bigger than 100 DutyCycle? (Sorry if i think something absurd)

Thanks.

cr0sh


Do you have any idea for wath is happening?


Because we are mind readers and can see your circuit...

HINT: Post a schematic and/or picture of your circuit, then maybe we can begin to help you - code might also be helpful, but maybe at a later stage.


Thanks.


You're welcome.
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

serbar

Here is the schematic hand made.

I will post a picture of the circuit i made.

Thanks.

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