Multimeter Fluke
2010
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 FLUKE 8520A DIGITAL MULTIMETER 8520 A $85.00 Time Remaining: 1d 13h 52m Buy It Now for only: $85.00 |
 Fluke True rms Industrial Logging Multimeter Fluke 289 $770.00 Time Remaining: 6d 18h 4m Buy It Now for only: $770.00 |
Multimeter Fluke
how do you get the internal resistance of the fluke 77 digital multimeter?
Most multimeters have an extremely high internal resistance so as to not draw too much current away from the circuit being measured. One best way to measure it is to build a circuit with a dc power source (say 5V) and two high resistance resistors of the same value (ie. 10MΩ) connected in series. Theory tells us that if we were to measure the voltage drop across one of the resistors, it should be 2.5V (Vr = Vdc*(R/2R) --> Vr = Vdc/2). However, when we measure the actual voltage drop, the theory doesn't hold true. What we have now is that we are measuring the voltage drop across the resistor that is in parallel with the internal resistance of the multimeter (Vr = Vdc * [ (R||Rm) / (R||Rm + R ]). Knowing Vr, Vdc, and R, one can solve for Rm (Meter internal resistance).
solarize fluke 189 multimeter
