Lesson 3 of 21
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Number Prefixes

NAC-Trainer April 29, 2020

Prefixes are commonly used in conjunction with electrical terminology. Most modern ‘Auto-ranging’ test equipment will also convert test readings into prefixes.

For example, when testing a Temperature Sensor (NTC) at 20 degrees we can expect the multimeter to show a reading of 6.05KΩ, this is 6050Ω

So it is very important to understand what the number prefixes are as-well as the electrical terminology.

A table of common electrical prefixes

These prefixes can commonly be found stamped on components, this can help to identify what test reading can be expected. Some test equipment will auto range and automatically show the prefix but some won’t.

When carrying out an insulation resistance test on the element pictured to the left. We get a reading of 0.127MΩ. Without the prefix, this is 127000 ohms.

The tumble dryer capacitor pictured to the right is labeled as 8µF. That is 8 microfarads. When testing this could also be displayed as 0.000008 farads.

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