9V +/- 20 percent (the usual allowance) gives 7.2 - 10.8 V. If you want anything more accurate than that you will need a calibrated meter. On Tue, 24 Apr 2012, Ed Johnson wrote: > 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 >> > wlevak@sdf.lonestar.org SDF Public Access UNIX System - http://sdf.lonestar.org Message was sent through the cbm-hackers mailing listReceived on 2012-04-25 05:00:14
Archive generated by hypermail 2.2.0.