ja, forstyrrer aflæsningen, når multimeteret tester små modstande?
Når multimeteret tester lille modstand, er der interferensstrøm, som vil generere forspænding og medføre målefejl.
When a multimeter is used for small resistance tests, the current source is usually relatively large (1 to 10 mA). Even so, the interference current still exists, and the bias voltage is more common in small resistance tests. A common error is caused by potential differences across different metal nodes. For example, a copper/tin-lead solder junction can generate a bias of 5 uV/ degree . Therefore, it is very important to reduce the number of nodes, and try to use metals of the same material. A copper/copper junction produces a bias lower than 0.3 uV/ degree , and choosing a smaller resistance range can improve test results. For example, Keysight's multimeter 34420A has 1 Ohm and 10 Ohm ranges and provides a larger current source of 10 mA to generate a larger voltage for easy measurement.
