Seriously, we need calibrated equipment? On Tue, Apr 24, 2012 at 6:57 AM, William Levak <wlevak@sdf.org> wrote: > On Tue, 24 Apr 2012, silverdr@wfmh.org.pl wrote: > > A question.. >> >> Since I have now quite a bunch of stuff sticking long way out of my >> EXPANSION port and also some from the tape port - I am thinking to >> eventually replacing my 30 years old and still reliable PSU. I have the one >> with two fuses and a power switch, which is quite rare and I wouldn't like >> to make it fail as it seems to get running quite hot with everything >> attached. Now - what's the problem you may ask. The problem and question is >> always the 9VAC. ALthough all the PSUs are rated at 9VAC, I recall that >> they supply somewhere between 11V and 12V. Moreover I recall that back in >> the days, when I supplied a "true" 9V of AC some things didn't work >> properly on the 64. I don't remember today what was failing but I remember >> that delivering a proper 9V didn't work out. Does anyone know why: >> >> a) why PSUs rated as 9V (have to) deliver 11+ >> > > Power supplies rated 9V appear to be at 11 or 12V, but actually are not. > The 9V rating means 9V effective voltage delivered to the equipment at full > power load. To measure this, you would have to put a resistor across the > power supply of sufficient wattage to match the maximum rated output of the > power supply, and then measure the voltage drop across the resistor. Of > course, you would also need a calibrated voltmeter in order to get an > accurate reading. > > > wlevak@sdf.lonestar.org > SDF Public Access UNIX System - http://sdf.lonestar.org > > > Message was sent through the cbm-hackers mailing list > Message was sent through the cbm-hackers mailing listReceived on 2012-04-24 18:00:42
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