Forum: Film SLRs and Compact Film Cameras
12-22-2017, 01:42 AM
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According the info from Pentax, the meter (the circled M uppercase on the schematic) has an internal resistance of 3 Kohm. They also say that the needle is centered when a current of 3uA (microAmp?re) traverses the meter. Hence a higher voltage battery will give a higher current at centre, so the needle will be off!
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Forum: Film SLRs and Compact Film Cameras
12-21-2017, 05:40 PM
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No, the voltage does matter. The bridge is loaded by the asa resistance when balanced against the output of the cd cell at 1.35 volts. I did a side by side comparison and the results for 1.55 and 1.35 volts were hugely different. Also using a 1.55 volt battery and an external light meter also gave huge diifferences
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