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Transistor Question

Bob Ross

May 27, 2017
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May 27, 2017
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I would like to use a Raspberry Pi 3 to control a motor i have a 9 volt dc motor ans batteries i got it working fine on its own but id like to wire it so i can write code on the pi to control it i see that i wire a power supply like the batteries i have and a input thing to control it but there is only one output and i dont understand what to connect it to the pi or the batteries i think if i hock it the the pi it will fry it and no current would flow through the motor but if i hook it to the batteries the transistor might not work please help me i dont understand how this should fit together at all.
 

Audioguru

Sep 24, 2016
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Sep 24, 2016
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The motor uses a certain amount of current and the transistor must be able to pass that current. But you did not say how much current the motor uses. The motor current is the highest when it starts running because that is when it is stalled. If you tell us its stalled current when it is powered from your battery then we can select a suitable transistor and show you how to connect it so it does not fry your pi.
 

Bob Ross

May 27, 2017
2
Joined
May 27, 2017
Messages
2
The motor uses a certain amount of current and the transistor must be able to pass that current. But you did not say how much current the motor uses. The motor current is the highest when it starts running because that is when it is stalled. If you tell us its stalled current when it is powered from your battery then we can select a suitable transistor and show you how to connect it so it does not fry your pi.
.8 amps
 

BobK

Jan 5, 2010
7,682
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Jan 5, 2010
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What you need depends on how you want to control the motor. If the motor only needs to run in one direction, a single MOSFET is all you need. If you need to run it in both directions, you need an H-bridge, which has 4 transistors.

Bob
 
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