See full version: How to Use an Ohmmeter
This article was co-authored by Daniel Stoescu. Daniel Stoescu is a Master Electrician and the Owner and Operator of Home Tech Solutions, LLC in Hampton, Virginia. With over a decade of experience, Daniel specializes in wiring residential, commercial, and light industrial structures. The Home Tech Solutions team has over four decades of combined experience and offers comprehensive solutions for residential electrical needs.
This article has been viewed 609,019 times. [links]
There are 7 references cited in this article, which can be found at the bottom of the page. more
This article was co-authored by Ralph Childers. Ralph Childers is a master electrician based in the Portland, Oregon area with over 30 years of conducting and teaching electrical work. Ralph received his B.S. in Electrical Engineering from the University of Louisiana at Lafayette and holds an Oregon Journeyman Electrical License as well as electrician licenses in Louisiana and Texas.
This article has been viewed 293,781 times. [links]
There are 10 references cited in this article, which can be found at the bottom of the page. more
Turn the meter’s function selector knob to the 20K resistance setting marked by the Ω symbol. [links]
Turn the function selector knob of the DM 350A counterclockwise to the 20-volt DC range, indicated by a V-- on the meter.
If the reading is zero, replace the meter’s internal fuse. The fuse is a 5 x 20 mm type rated at 1/2 amp and 250V.
Touch the black meter probe to the unconnected lead of the resistor. Touch the red meter probe to the positive terminal on the battery. [links]
Plug the red meter probe into the meter’s mA jack. Plug the black probe into the COM jack. here
Touch the metal tip of the red probe to the battery’s positive terminal. Touch the tip of the black probe to the negative terminal. more
Then, it’s time to remove the black lead from the slot and insert it into the oval slot. This section of the electrical outlet is the ground and you will soon see a voltage reading. If no reading is displayed you may have a blown fuse or the circuit breaker may be tripped. [links]
The black lead will be inserted into the left vertical slot of the wall outlet. Now it will be time to check to see what reading you are receiving. Typically, you should receive a reading between 110 and 120 VAC. This all depends on the power levels the utility companies are supplying. If your multimeter continues to show 0.0 you may have a bad connection, try wiggling the leads for better contact. If this does not help you may have an electrical problem with your outlet. here
These diagnostic steps are used to help locate electrical problems in a number of different sources. A digital multimeter gives automatic, quick readings that display VAC (volts alternating currents), VDC (volts direct current), and ohms. Testing an electrical outlet using a digital multimeter in your home, you will need to use the VAC reading available on the device because you are looking for a measurement of Alternating Current Voltage. If you want to know more about AC and DC power, this article is a must-read, The War of the Currents: AC vs. DC Power, from the Department of Energy.
And, for a deeper dive, try this tutorial on measuring resistance with a DMM.
Next, you will need to connect the black lead, this is done by connecting it to the “com” label. Note – The red lead may have a red ring around the connector and the black lead may have a black ring. As mentioned above, you will be using the “VAC” or volts option on the multimeter. So make sure the digital multimeter is in this setting. Each multimeter is different which means yours may read 0.0 VAC, VAC, or only 0.0. Once this is set, you are ready to begin testing. more