Alt-BEAM Archive
Message #00760
To: "'Ben Hitchcock'" beh01@uow.edu.au, beam@corp.sgi.com,
From: Wilf Rigter Wilf.Rigter@powertech.bc.ca
Date: Mon, 22 Feb 1999 00:44:13 -0800
Subject: [alt-beam] Re: It works, but I don't know how... new diagram
content-type: text/plain
Not expecting it on the BEAM list?
The designer's own explanation always helps! Ofcourse the pulse generator
itself consumes power since it also operates in the linear region part of
the time. Anyway I tried the sensor latch with the 3 diodes to the V+ and it
seems to work quite well.
Strangely, the resistor to ground is quite critical: 51K worked great but
100K not at all. Also saved one diode which should work in your circuit as
well. See attached GIF.
<>
Wilf Rigter mailto:wilf.rigter@powertech.bc.ca
tel: (604)590-7493
fax: (604)590-3411
> -----Original Message-----
> From: Ben Hitchcock [SMTP:beh01@uow.edu.au]
> Sent: Monday, February 22, 1999 9:22 AM
> To: beam
> Subject: Re: It works, but I don't know how... new diagram
>
> It's nice to see one of my circuits cropping up where I wasn't expecting
> it!
>
> >
> >Looks like you were missing a pull-up resistor on 245 pin 19 so the
>
> Yep, I agree.
>
> >
> >Anyway here are some questions and suggestions for improvements for you.
> >
> >What's the narrow pulse generator for?
>
> It's because any circuit that latches on above a certain voltage consumes
> heaps of current as it approaches the switch-on voltage. I usually play
> around with tiny solar cells, and without the pulse generator the circuit
> quite often won't switch on. With the pulse generator the circuit onyl
> checks the voltage a tiny fracction of the time. The rest of the time is
> spent doing nothing.
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Attachment: sensomem.gif
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