Comparison of H-bridges

Thread Starter

Dritech

Joined Sep 21, 2011
901
Hi again,

With reference to the attached h-bridge diagram, what will happen if both inputs are low ?? will that supply the motor with 12V on both terminals ??
 

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Audioguru

Joined Dec 20, 2007
11,248
With reference to the attached h-bridge diagram, what will happen if both inputs are low ?? will that supply the motor with 12V on both terminals ??
No.
The transistors are inverters and the Mosfets are also inverters.
Both terminals of the motor will be 0V and it will act like a brake.

If both inputs are high then the motor will have +12V on both terminals and it will also act like a brake.

The motor will not free-wheel and PWM speed control will waste a lot of power.
 

Thread Starter

Dritech

Joined Sep 21, 2011
901
If both inputs are high then the motor will have +12V on both terminals and it will also act like a brake.
And can that damage the motor? or will it increase the current consumed when 12V is applied to both terminals?
 

Audioguru

Joined Dec 20, 2007
11,248
I don't think electrically braking a motor will damage it unless something is turning it (causing it to be a generator) when it is shorted.

The 12V will have NO current when the motor is shorted.
 
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