Electrical Resistance Converter
Same value in every unit
| Unit | Value |
|---|
Where each range lives
- Milliohms — connectors, busbars, battery internal resistance
- Ohms — speakers, heating elements, motor windings
- Kilohms — most circuit resistors, pull-ups, dividers
- Megohms — insulation, high-impedance inputs, leakage paths
- Gigohms — insulation testing and electrometer work
Why wet hands change everything
Dry skin measures around 100 kΩ, so 230 V drives roughly 2 mA through you — unpleasant and not usually dangerous. Wet skin can fall to about 1 kΩ, and the same 230 V now drives something near 230 mA, which is well past the fatal threshold. The voltage did not change; your resistance did.
Measuring very small resistances
Below about an ohm, the resistance of your own test leads becomes a significant part of the reading. That is what four-wire measurement solves: two leads carry the current, two separate ones sense the voltage, so the leads drop out of the answer.
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Frequently Asked Questions
Voltage equals current times resistance — V = I × R. Rearranged, current is voltage divided by resistance, which is how you work out what a component will draw before you connect it.
Roughly 100 kΩ dry skin to skin, but only 1 kΩ or so when wet or when the skin is broken. That hundredfold drop is why the same voltage that is harmless with dry hands can be lethal in a bathroom.
Insulation testing. A cable in good condition reads tens or hundreds of megohms between conductor and earth; a reading in the kilohms means the insulation has failed. Multimeters that stop at 20 MΩ are not much use for it.
Contacts, connectors, battery internal resistance and cable runs, where a few thousandths of an ohm carrying hundreds of amps generates real heat. They need a four-wire measurement — an ordinary meter measures its own leads.
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