How to read the resistance of a digital multimeter
Digital multimeter measuring resistance
A multimeter measures resistance by outputting a small current to a circuit. Standard units are ohms (Ω). Since current flows through all possible paths between the probes, the resistance reading represents the total resistance of all paths between the probes.
The resistance range of the multimeter has segmented gears, such as Fluke 87V/C, the resistance range is 600.0 Ω, 6,000 kΩ, 60.00 kΩ, 600.0 kΩ, 6,000 MΩ and 50.00 MΩ. To avoid damage to the multimeter or the equipment under test, before measuring resistance with the digital multimeter, please turn off the power of the circuit and discharge all high-voltage capacitors.
Steps for measuring resistance with a digital multimeter
1) Disconnect power from the circuit
2) Select the resistance file (Ω).
3) Insert the black test probe into the COM input jack. Insert the red test probe into the Ω input jack.
4) Connect the probe tips at both ends of the element or short-circuited part whose resistance is to be measured.
5) For the reading, be sure to note the unit of measurement – ohms (Ω), kiloohms (kΩ) or megaohms (MΩ).
1,000 Ω = 1 kΩ 1,000,000 Ω = 1 MΩ Make sure the power is off before making resistance measurements.
Here are some tips for measuring resistance with a digital multimeter:
1) Because the test current of the meter flows through all possible paths between the two probes, the resistance value measured on a resistor in the circuit is usually different from the resistor's rated value.
2) When measuring resistance, the test lead will bring an error of 0.1 Ω to 0.2 Ω. If you want to measure the resistance of a wire, you can touch the probe tips together and read the resistance of the wire. You can use the multimeter's relative value (REL) mode to automatically subtract this resistance value if desired. (For the use of the relative value function, please refer to the Fluke multimeter resource website)
3) In the resistance mode, the voltage output by the ammeter is enough to turn on the forward bias voltage of the silicon diode or transistor on the circuit. If in doubt, press C to apply a lower current on the next higher range. If the resulting value is larger, choose the larger value. Continuity is a quick "go/no-go" resistance test that distinguishes between open and closed circuits.
