Try measuring a 2 milliohm contact resistance with a standard multimeter and you'll get noise, not data. Below roughly one ohm, lead resistance and contact resistance swamp the reading — which is exactly the problem a milliohmmeter is designed to solve.
What Is a Milliohmmeter?
A milliohmmeter is a precision instrument designed specifically to measure very low resistances — from single milliohms down to micro-ohms — accurately and repeatably. It does this using a four-terminal (Kelvin) measurement technique, which separates the current-carrying leads from the voltage-sensing leads so that lead and contact resistance don't corrupt the reading.
Key Specifications to Consider
- Resolution — the smallest resistance change the instrument can distinguish, critical for weld and contact quality checks
- Test current — higher test currents improve signal-to-noise ratio on very low resistances
- Four-terminal (Kelvin) connection — essential for eliminating lead resistance error
- Insulation resistance measurement — many models combine milliohm and high-resistance/insulation testing in one instrument
Typical Applications
Milliohmmeters are widely used to verify weld and connector contact resistance, battery and busbar internal resistance, motor winding and transformer resistance, and cable/harness continuity in production quality control.
Milliohmmeters from ALLdata
Our range includes the GW Instek GOM-805, the GW Instek GOM-804, and the Chroma 16502, which combines milliohm and insulation resistance measurement in a single instrument. Contact us to find the right resolution and test current for your application.