To: | Steve Thompson <g8gsq@ic24.net> |
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Subject: | Re: [Amps] Current draw at 110 volts for SB-200 and SB-1000 |
From: | Vic Rosenthal <vic@rakefet.com> |
Date: | Fri, 03 Dec 2004 11:02:32 -0800 |
List-post: | <mailto:amps@contesting.com> |
Steve Thompson wrote:The high current 'gulps' I meant are the ones every line half cycle, not at syllabic rate. The line voltage your meter measures tends to reflect a cycle to cycle average, and doesn't indicate what happens during those few ms whereas the psu feels the full effect. If you put a scope across the primary of the transformer, you might see a distorted waveform due to the large current drawn during part of the cycle. But the output voltage of the supply is related to the voltage that appears across the filter capacitors. This total charge is (I would guess) proportional to the area under the curve of the distorted waveform I mentioned. So the resultant output voltage drop due to the resistance in the circuit feeding the PS is an average (of some kind) of the voltage drop across the primary over the period of the cycle multiplied by the square of the turns ratio. Another way of putting this is that although the voltage drop due to the power line resistance varies greatly during the cycle, the capacitors even it out. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps |
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