Resistance is measured in Ohms and can tell you how well a circuit or component is performing. For a reading of 25 amps the meter would display 250 millivolts. While you’ll be hard-pressed to find a digital multimeter that doesn’t measure voltage, your HVAC multimeter should be able to measure AC voltage up to 600V and DC voltage up to 300V. Make sure your multimeter can at least measure up to 5 MΩ (that’s 5 megaohms) in increments of 1/10 Ω. Set the meter's function switch to read ac voltage or ac millivolts. This zero adjust is only required for dc measurements. Then touch the red positive probe on the multimeter to the positive terminal on the power source and the black negative probe on the multimeter to the negative terminal on the power source. Saving Electricity: How Much Electricity Do Household Items Use. Multiplying the voltage in a circuit, with the current flowing in the circuit, will give … In this video, I have shown how to measure AC current or Amps with Clamp Multimeter on the 240v circuit. Accessory current clamps expand a multimeter's flexibility and measurement capabilities by allowing it to measure up to thousands of amps. Multiplying the voltage in a circuit, with the current flowing in the circuit, will give us the total power in the circuit, represented in watts. A reading of 10 amps would display as 1,000 millivolts or 1 volt. Households have AC while power houses from the battery are DC. Where the voltage meter measures the capacity of your electrical circuit, the amperage meter measures the bandwidth that’s actually being used. Place the clamp jaws around only one conductor of the circuit to be tested. Use the 100 millivolt per amp position for accurate current measurements up to 10 amps and the 10 millivolt per amp position for current measurements exceeding 10 amps but less than 100 amps. For example, if you measured a car battery to have 12 volts, and the current flowing at 5 amps, there would be 60 watts of power flowing in the circuit, enough to light a 60-watt light bulb. With the power flowing in the circuit, adjust the dial on the multimeter to measure voltage (AC or DC). If it reads 0 ohms, you’re good to go. Turn on the digital multimeter. Measure the current flowing in the circuit. Set the multimeter dial to AC or DC mode. 80i-110s is also an ac/dc Hall Effect Type clamp. It’d be nice if you could rely on your reading and not wonder if you’ve got a false positive. Set the meter's function switch to read dc millivolts. Even when the ability to read temperatures isn’t a requirement, it’s a great feature to have that will make life a lot easier when you’re trying to work with HVAC appliances. She has years of experience as a professional of the English language employed with the "Cape Times" and "The Mercury." Clamping around both the line and neutral conductors (like a line cord) at the same time will cancel the current flow reading. Your email address will not be published. For the smaller A measurements, make sure your digital multimeter can read as little as 1/10 of a microamp. The first thing to do is to test your meter. For dc current measurements, plug the black output connector into the meter's common jack and the red output connector into the meter's V/? But if you can have a multimeter that includes temperature probes, it will save you space, time, and effort. The model that comes to mind first is the Fluke 116. After this, check the owner’s manual for the amperage rating. Convert amp to microamp here: Measurement unit conversion. This clamp was originally designed for use with an oscillioscope and terminates with a BNC style connector. In this blog post, we’ll show you what to look for in a digital multimeter when you’re planning to apply it to HVAC appliances, and which features will make the biggest difference. Set the meter's function switch to read AC millivolts or AC voltage. 10 amps, the probe output is 100 mV/A. The reading on the Fluke 289 True-RMS Data Logging Multimeter display (225.32 mA ac) corresponds to a true circuit current of 225.32 amps ac.