Alt-BEAM Archive
Message #04457
To: beam@sgiblab.sgi.com
From: davidperry@mail.geocities.com
Date: Fri, 12 Jun 1992 09:22:29 +0000
Subject: [alt-beam] Re: bypassing a nv
> OK, nice & simple. Assuming you have a typical Nv with a resistor going
> to ground at the input, all you have to do is use your switch to short
> the resistor.
won't this act as a PNC?
> Better motors is always the preferred solution, for those can get them
> and don't mind the price. I've been using a 6 transistor h-bridge with
> good results. The one Ian shows at BEAM online
>
> http://www.beam-online.com/Robots/Circuits/circuits.html
>
> can handle 100 mA. I substituted the following transistors to handle up
> to 500 mA:
>
> Replace the TOP row of (PNP) 2N3906 transistors with PN2907
> Replace the BOTTOM row of (NPN) 2N3904 transistors with PN2222
> Middle row stays the same unless ... (see below)
>
> The ones I have are exactly the same physical size as the ones they
> replace. Pinout orientation is also the same. My Motorola datasheet
> actually gives these a maximum rating of 800 mA, but recommends 500 or
> less. You should be able to use even bigger transistors if necessary.
>
> What configuration are you using for your Nv loop(s)? Master-slave
> bicore? Microcore with a 4 Nv loop? Reason I ask is this may affect
> which type of transistor you use in the middle row of Ian's diagram.
> Also, if you're using a 4 Nv loop you may need some protection to
> prevent both sides of an H-bridge from turning on at the same time.
4NV loop
____________________________________________
I'm sure David sinceraly apologises if he
insulted anyone, it won't happen again.
____________________________________________
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