From: Mike Poulton
Subject: Re: Urgent help needed to blank monitor
Date: 5 Nov 2002 00:51:27 GMT
Organization: MTP Technologies
"Ulrich Peters" wrote in message
> Ok, this is my idea, and now I need some help. Can somebody tell me
> what components would be the most appropriate for this circuit? I
> think that the currents of the sync signals are pretty low, but I
> don't have any instruments to measure them. What thyristor/triac
> could I use, and how should I connect the TTL output to the gate? (If
> this is a good idea at all. If you see that this won't work at all,
> please tell me.)
I would not recommend using thyristors for the sync lines. It might
work, but it probably won't. It might be much easier to use reed
relays. They can be driven from a TTL signal (though you need one gate
each) and give you complete isolation. While you certainly could use
discrete gates to make a parallel port activated switch, a PIC
microcontroller might be simpler, cheaper, and easier. Ganging a few
output pins on the PIC together would allow you to drive a pair or reed
relays with no problem. Alternatively, you could drive a power mosfet
with the logic signal, and use that to activate a relay that controls
main power to the monitor.
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