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This article was co-written by Ricardo Mitchell. Ricardo Mitchell is general manager of CN Coterie, an EPA-certified construction company based in Manhattan, New York. CN Coterie specializes in home improvement, electrical, plumbing, carpentry, furniture restoration, dismantling of OATH/ECB violators, and dismantling of DOB violators. Ricardo has more than 10 years of experience in the electrical and construction industry, his associates have more than 30 years of experience in the related industry.
There are 8 references cited in this article that you can see at the bottom of the page.
This article has been viewed 3,743 times.
A voltmeter is one of the most useful devices for home electrical testing if you use it correctly. If this is your first time using a voltmeter, you should learn how to set up the device and test it on a low-voltage circuit, such as a household battery.
This wikiHow teaches you how to check voltage. You’ll probably also want to learn how to use a multimeter to measure amperage and resistance.
Steps
Device settings
- To check the AC voltage, turn the knob to V~ , ACV or VAC mode. Household electrical circuits are mostly alternating current.
- To test the voltage of DC current, you need to select V– , V— , DCV or VDC . Batteries and portable electronic devices both use direct current.
- Select a setting higher than the maximum expected voltage. If you do not know this parameter, choose the highest level to avoid damage to the device.
- Household batteries will have a label showing the voltage, usually 9V or less.
- Car batteries have a voltage of about 12.6V when fully charged with the engine off. [2] X Research Source
- In most countries around the world, the power source in the house is usually 240V. In Vietnam, the standard voltage is 220V. [3] X Research Sources
- mV is the symbol for millivpt or ( 1 / 1000 V), this unit is sometimes used to indicate the lowest setting level.
- The black jack always plugs into the hole labeled “COM”.
- When measuring voltage, you need to plug the red jack into the hole labeled V (among other symbols). If there is no V symbol, select the hole with the smallest unit of measurement or mA .
Measure voltage
- Two metal probes should never touch each other while connected to a circuit, otherwise dangerous sparks may result.
- On the battery, touch the black probe to the cathode.
- With a wall outlet, insert the black probe into the hole with the cold (or neutral) pin. You should use an electric tester to check first. If the light on the pen doesn’t come on, it’s a hole with a cold pin.
- Check the black probe and remove the small protruding plastic knob (if any) before proceeding, as this piece of plastic can become lodged in the electrical outlet.
- For the battery, you need to connect the red probe to the positive terminal.
- On an electrical outlet, plug the red probe into the hole with the “hot” pin. You should use an electric tester to check first. If the light on the pen comes on, it’s a hot pin hole.
- The digital display shows “OL”, “overload” or “1”. [5] X Trusted Source Science Buddies Go to Source Note: “1V” is a true reading and nothing to worry about.
- The analog needle jumps to the other side of the scale.
- Check that the probes are in contact with the electrical circuit.
- If you are measuring DC circuits and there are no results, find the small knob or switch labeled DC+ and DC- on the unit and switch to the other setting. [6] X Study Source If the instrument does not have this option, you need to swap sides of the red and black probes.
- Decrease range by level. Keep decreasing until you get a real reading.
Read needle voltmeter
- For example, if the voltmeter is in DC 10V mode, you need to look at the scale with a maximum reading of 10. If not, look for a scale with a maximum reading of 50.
- For example, if the needle is pointing between 30 and 40, the reading is 35V.
- For example, if the voltmeter is on the 10V setting but you read it on the 50V scale, take 50 ÷ 10 = 5 . If the needle is pointing at 35V, your actual voltage is 35 ÷ 5 = 7V.
Advice
- The instructions for checking the voltage in the electrical outlet above assume that you are trying to determine the voltage passing through the device that will use this power source. If you want to identify a line problem, you need to measure the voltage between the ground and the other hole. If the measured voltage is low (such as 2V), this is a cold pin and you have just performed a voltage drop (voltage drop). If you get a high reading (eg 110V or 220V) then this hole is the hot wire pin. [7] X Research Sources
- If testing a wall outlet, measure the vertical pins. For 3-pin sockets, the round hole is the ground wire pin, so you don’t need to check.
Warning
- If used improperly, the device may be damaged, you may receive a serious electric shock, or create a spark that can cause a fire. Testing a socket or other high voltage circuit is more risky than measuring voltage on a low voltage battery. If you just want to practice measuring and reading on a voltmeter, do it on a household battery.
This article was co-written by Ricardo Mitchell. Ricardo Mitchell is general manager of CN Coterie, an EPA-certified construction company based in Manhattan, New York. CN Coterie specializes in home improvement, electrical, plumbing, carpentry, furniture restoration, dismantling of OATH/ECB violators, and dismantling of DOB violators. Ricardo has more than 10 years of experience in the electrical and construction industry, his associates have more than 30 years of experience in the related industry.
There are 8 references cited in this article that you can see at the bottom of the page.
This article has been viewed 3,743 times.
A voltmeter is one of the most useful devices for home electrical testing if you use it correctly. If this is your first time using a voltmeter, you should learn how to set up the device and test it on a low-voltage circuit, such as a household battery.
This wikiHow teaches you how to check voltage. You’ll probably also want to learn how to use a multimeter to measure amperage and resistance.
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