Truth Or Consequences?
http://www.solar-electric.com/mkb-500-50.html http://www.circuitspecialists.com/lcd-panel-meter-pm-328.html Provide circuit power from a nine-volt lithium battery and this ammeter will offer u...
Forum Discussion
Most of the time you don't need an expensive voltmeter, but anyone counting on a battery voltage to reflect the state of charge knows that a tenth of a volt means 20% of the useful upper half of the charge. I have cheapo multimeters but they do have a calibration potentiometer on the circuit board. Now, where to find an accurately known voltage? A new Duracell AA cell is supposed to be 1.65 volts. The fully charged lead acid battery is supposed to be 12.65. I bought a voltage reference source on eBay for ten dollars and I think it is sufficiently accurate. My cheapo meters seem to retain their calibration well over 6 months. They are a thrifty man's Flukes.
