Alt-BEAM Archive
Message #11838
To: beam@sgiblab.sgi.com
From: Bruce Robinson Bruce_Robinson@telus.net
Date: Tue, 14 Mar 2000 18:05:10 -0800
Subject: [alt-beam] Re: H-Bridge
Andrew Hooper wrote:
> ... I found the problem with using 4 transistor h bridges, either
> you end up with a 0,0=smoke or a 1,1=smoke :(
The same is true of the 6-transistor bridge, Andrew. Mark Tilden added a
74HC139 chip to his 6-transistor bridge design to prevent smoking. It
basically takes the two inputs and decodes them into a one-of-four
output. Two of the outputs are used to trigger the bridge, and it is
impossible for more than one to be "on" at the same time. The same chip
can be used on 4-transistor bridges.
Smoking bridges is not usually a problem with bicores, as only one
output can be "on" at one time. However, it is potentially a serious
problem with 4 or more Nv's.
The original Tilden paper is referenced on the new Circuits section of
the BEAM Web Index, as are Wilf's various smokeless 4-transistor
designs.
Bruce
11839 Tue, 14 Mar 2000 21:07:32 -0800 [alt-beam] Re: 1000k pots beam@sgiblab.sgi.com Laura Malinowski Laura/Rob Malinowski actually Ben they end up in a place very close to where all those single
socks that seem to get lost in the dryer go
Ben Hitchcock wrote:
> This message is being sent for the second time. Apologies if you get it
> twice. I wonder what happens to all the e-mails that get sent but don't
> go to where they're going? Do they end up in the electronic equivalent
> of the 'back store'?
>
>
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