The Amprobe MO-100 digital milliohm meter measures resistance up to 2,000 ohms in automotive, industrial, and heating, ventilation, and air-conditioning (HVAC) applications. It has four input terminals for taking four-wire resistance measurements, which are more accurate than two-wire resistance measurements. It has a minimum resolution of 100 microohms for measuring small amounts of resistance. The meter offers a choice of three test currents for more precise readings. Over-temperature and over-voltage warnings help prevent damage to the meter. The meter comes with four test leads with alligator clips that provide hands-free connection to conductors up to 0.67" (17 mm) in diameter. The test leads have a shrouded plug that helps protect against shock if the leads are accidentally pulled out of the meter during use. The meter's hold function keeps a reading on the display, even after meter is disconnected. The meter has a liquid crystal display (LCD) with a 2,000-count resolution, meaning that it can display up to 1,999 units (3-1/2 digits) before the operating range needs to be changed. It is a manual-ranging meter and requires the operator to choose the appropriate operating range for the property being measured. The MO-100 milliohm meter conforms to International Electrotechnical Commission (IEC) safety standard 61010, European Conformity (CE) directives, and Australian N10140 guidelines. The meter operates on eight AA batteries (included). Auto power-off feature turns off the unit after 30 seconds of non-use to conserve battery life. It comes with a shoulder strap for hands-free carrying.
|Maximum resistance detected ||2,000 ohms|
|Test current supplied at 2,000 ohm range ||1 milliamp|
|Test current supplied at 200 and 20 ohm ranges ||10 milliamp|
|Test current supplied at 2,000 milliohm and 200 milliohm ranges ||100 milliamp|
|Minimum resolution ||100 microohms|
|Fuse ||0.5 amp/ 250V fast-blow ceramic fuse (one, installed; one, spare)|
|Power supply ||1.5V AA batteries (eight, included)|
|Weight ||3.3 lb./1.542 kg|
|Dimensions ||9.8 x 7.5 x 4.3 inches/110 x 250 x 190 mm (H x W x D)|
H is height, the vertical distance from the lowest to highest point; W is width, the horizontal distance from left to right; D is depth, the horizontal distance from front to back.
Ohmmeters measure resistance in an electrical component or circuit and check the continuity of an electrical circuit. Micro- or milliohm meters measure small values of resistance, and megohmmeters (also known as megaohmmeters or meggers) measure large values of resistance. Ohmmeters have an internal power supply, such as a battery or a capacitor, that supplies current to a circuit or component that is turned off. Test leads are connected in series to the meter and circuit or device under test, and as current flows through the circuit or device, the meter calculates the difference in voltage between the leads and measures the resistance. Ohmmeters measure resistance using either the two-wire or four-wire method. The two-wire method is easier to set up than the four-wire method, but it provides less accurate measurements because it includes not only the resistance of the circuit or device under test but also the resistance of the test leads. The four-wire method measures only the resistance of the circuit or device under test, providing more accurate readings and allowing the meter to measure smaller values of resistance than the two-wire method.
Amprobe manufactures electrical testing equipment for commercial, industrial, and home use. The company was founded in 1948 and is headquartered in Everett, WA.
What’s in the Box?
- MO-100 milliohm meter (4) Test leads (one red, one green, one blue, one black)
- (8) 1.5V AA batteries (installed)
- (2) 0.5 amp/ 250V fast-blow ceramic fuse (one installed, one spare)
- (1) Shoulder belt