Re: [beam] H-bridge
- provides a much higher current to an electrical motor than signal
transistors or most chips can, also enables bi-directional control and
PWM. generally needed for any motors much larger than your thumb. There
are H-bridge ICs such as the L293 that can be used instead of building
them from discrete parts, though it does have a limited current ability
before it melts.
> David Wilson wrote:
> I've been wondering. What exactly does an H-bridge do?
> Dave Wilson
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- it amplifies current, but as i've never tested it, im not sure by how much.
--- David Wilson <ik0153@...> wrote:
> I've been wondering. What exactly does an H-bridge do?__________________________________________________
> Dave Wilson
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- This is perhaps the simplest way to describe an H-bridge: the bicore,
microcore or any other circuit you are using determines what voltage the
motor should be supplied with. The H-bridge makes ssure that the motor get's
enough current to run on that voltage. See it as a current amplifier. 2N390X
gives 100 Ma. 2N2222/2907 gives 800 Ma. BC 639/640 gives up to 1 Amp. I
prefe these since they are a lot cheaper cheaper than 2N2222/ 2N2907, and
are more flexible in current than 2N390X.
For currents around 100 Ma I recommend the 74xx245 driver.
>From: "Tyson B." <tb1144@...>_________________________________________________________________________
>Subject: Re: [beam] H-bridge
>Date: Thu, 1 Feb 2001 16:01:47 -0800 (PST)
>it amplifies current, but as i've never tested it, im not sure by how much.
>--- David Wilson <ik0153@...> wrote:
> > I've been wondering. What exactly does an H-bridge do?
> > Thanks,
> > Dave Wilson
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