Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: roi_tau on November 27, 2008, 08:55:32 AM
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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
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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
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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
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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.
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make sure your transistor isn't flipped or something.
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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).
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The proper way would be to use a MOSFET and no resistor ;D
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You mean like the 2N7000?
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You mean like the 2N7000?
yes, and any PWM optimized MOSFET ;D
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Hi Admin
I didnt understand your answer.
Roi
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You mean like the 2N7000?
yes, just like the 2N7000.
Also, just like any MOSFET that is PWM optimized.
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I didnt understand the part of the PWM optimized.
What do you mean by that?
Roi
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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 :P