Probably the memory can be powered externally. A 3 volt battery and a
couple schottky diodes to allow the higher voltage of the 3 volt battery
or the 5 volt supply to run the memory, maybe a resistor in series with
another diode to charge the 3 volt battery in NiCad. Could be a three
cell NiCad packaged for a cordless telephone, 4.5 volts. Charge from 12
volts with enough resistance to limit the current to maybe 6 ma for the
typical 120 mah cordless phone battery. Otherwise no charging for a
standard lithium cell. What is the memory chip? Who made it?
73, Jerry, K0CQ
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Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.
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