Problem to activate DC motor

[roi_tau]

Hi Guys.

My Robot should activate little vibration motor.

The schema is attached

My battery is 3.6 volt (3 cells) Ni-MH

The base is connected strait to the uC with no resistor (It doesn't work with R>0.5K)

What do you think?

Is my values correct?

The circuit works but I want it to be correct.

Roi

[jamort]

you might want to make sure the motor works.... plug a battery into it with out it in the circuit.....
I think you said basically doesn't work from the get go because if it stopped working it could of been to much voltage

[roi_tau]

The motor works with and without the circuit


I just want to know if the way I connected it is right,(Wont damage the transistor in the long run)

Roi

[ArcMan]

That circuit is fine for such a small motor.  BTW, don't use the 30 ohm resistor unless you intend to measure the motor current.  That's what it's for.

[szhang]

make sure your transistor isn't flipped or something.

[ArcMan]

Ooh.  I just read your OP more thoroughly.  You must have a resistor between the uC and transistor base or you'll kill your transistor.  Take out that 30 ohm resistor on the emitter and use about a 500 ohm resistor on your base.  That arrangement will switch about 100 mA if the transistor hfe is 50 (which is typical for a bipolar switcher like a 2N2222).

[Admin]

The proper way would be to use a MOSFET and no resistor

[roi_tau]

You mean like the 2N7000?

[Admin]

You mean like the 2N7000?

yes, and any PWM optimized MOSFET

[roi_tau]

Hi Admin

I didnt understand your answer.


Roi

[Admin]

You mean like the 2N7000?

yes, just like the 2N7000.

Also, just like any MOSFET that is PWM optimized.

[roi_tau]

I didnt understand the part of the PWM optimized.

What do you mean by that?

Roi

[Admin]

Optimized for PWM:
http://www.societyofrobots.com/member_tutorials/node/228

To operate a DC motor, you need to PWM your MOSFET. A PWM optimized MOSFET will give you a higher efficiency. You'll see 'PWM Optimized' typically on the very first page of the MOSFET datasheet.

And remember to google before asking questions