Re: Power Consumption Measurements for an HP-41CX Message #3 Posted by Dan Grelinger on 28 May 1999, 8:37 a.m., in response to message #2 by Reinhard Hawel
I have most of the HP-41 accessories, and plan on measuring power requirements of each, indirectly through the HP-41. I expect that the card reader will pull much more than 20mA, probably over 100mA, when it is pulling a card. I believe that there was a technical article in the HP Journal about the card reader in 1979 or 80, that described the peak current draw close to an amp, essentially a spike when the card reader motor first turned on. I have an auto-ranging meter, but I will have to lock it down on the appropriate scale to get a proper measurement. It provides practically instant approximate measurement, (through a bar-graph), and updates the precise displayed value about every 1/2 second, so I should be able to capture peak current draw, as well as estimate the average.
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