Alt-BEAM Archive

Message #01015



To: Chris Daniel popjester@hotmail.com
From: Steven Bolt sbolt@xs4all.nl
Date: Fri, 26 Feb 1999 10:33:04 +0100 (CET)
Subject: [alt-beam] Re: H-bridges and mercury switches


On Thu, 25 Feb 1999, Chris Daniel wrote:

> Are H-Bridges as demanding on what kinda transister to use as solar
> engines are? Most of my transisters don't very well for SEs ut I want to
> use them for 2 H-Bridges for my walker (hopefully that'l make it move :)

Even more demanding, actually. An H-bridge puts two VCEsats in
series with your motor, so to achieve efficiency, the transistors
need to have a low VCEsat at the collector current wanted by the
motor. And of course, base current musn't be too high either. Not
more than a few mA if it is to be supplied by a 74HC output.

Best,

Steve

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# sbolt@xs4all.nl # Steven Bolt # popular science monthly KIJK #
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