In addition to a resistance value, measured in ohms, it has a maximum power rating, measured in watts. share | improve this question | follow | asked Feb 16 '11 at 22:12. endolith endolith. She has conducted survey work for marine spatial planning projects in the Caribbean and provided research support as a graduate fellow for the Sustainable Fisheries Group. You can identify the level of resistance of a given resistor by the number and colors of the bands on it. Thank you much. Not necessarily! For example, you might test the resistance of the switches, relay contacts, or motor. unlocking this expert answer. Resistance is the measure of difficulty electrons have in flowing through a particular object. Depending on the multimeter you’re using, the effect of direct contact with components on the reading may be negligible. Research source IMPORTANT: There's a good chance that you won't see exactly the resistance values I've listed (on your multimeter). It automatically subtracts test lead resistance—typically 0.2 Ω to 0.5 Ω. If the resistor is in circuit, you will generally have to remove the resistors in the board so you are testing only the resistor value and not the other … A resistor is a standard electronic component that has a constant electrical resistance in a circuit. "Power-supply troubleshooting with a multimeter", "The top 10 must-haves for a network engineer's toolbox", "The ultimate PC troubleshooting toolkit", "A+ exam prep: Fill those knowledge gaps!". If it has a kΩ in the corner, the actual resistance is 58 kΩ (58,000 ohms). Disconnect the fuse to the headlight. Click on another answer to find the right one... Why might you use alligator clips to hold components while testing, rather than holding them in your hands? The middle of the range is usually 20 kiloohms. Plug the black lead into the socket labeled "COM" and the red lead into the socket labeled "ohm". Check the reading to determine if the resistor is good. If the screen reads OL (overloaded) the range is set too low and needs to be increased to the next highest range. Ensure the needle is set all the way to zero using the Ohms Adjustment or Zero Control after the leads have been touched to each other. Bess Ruff is a Geography PhD student at Florida State University. When the blower motor resistor fails on your GMC pickup or SUV, the blower motor will only work in one speed and in a few cases not at all. At bright light, the LDR resistance will be around 500Ohms and at darkness the resistance will be around 200K. Understanding Bash: A guide for Linux administrators, Checklist: Managing and troubleshooting iOS devices, Comment and share: How to use a multimeter to test resistors. Start with a fully charged battery. Only one of these answers is correct here! Read on for another quiz question. If your starting range is too high, the needle will swing to the bottom of the range, which is the left side of the multimeter. wikiHow is where trusted research and expert knowledge come together. Alligator clips are useful for preventing this interference. Read on for another quiz question. Testing a Resistor with an ohmmeter is the best, easiest and most effective way to tell whether a resistor is good or not. Use the lowest range setting for the most accurate resistance readings. It was like going back to college. You can check the resistor resistance by selecting the ohmmeter range in the analog and digital multimeter. That’s because the multimeter will inject a known voltage into the circuit […] By signing up you are agreeing to receive emails according to our privacy policy. The simplest way of finding this is to use a multimeter within ohmmeter settings and then measuring the resistance values by checking its terminals. ", Unlock expert answers by supporting wikiHow, http://www.physicsclassroom.com/class/circuits/Lesson-3/Resistance, http://en-us.fluke.com/training/training-library/test-tools/digital-multimeters/how-to-measure-resistance.html, http://www.electronics-radio.com/articles/test-methods/meters/multimeter-resistance-measurement.php, https://learn.sparkfun.com/tutorials/how-to-use-a-multimeter/measuring-resistance, consider supporting our work with a contribution to wikiHow. Test a Resistor with an Ohmmeter. This article has been viewed 349,503 times. In order to test a resistor, it is important to first disconnect one lead from the circuit.. it won't matter which one. We go through several different tests, all using a multimeter. Right! That implies a low resistance between them. The number on the screen will either be 0.00, OL, or the actual value of resistance. How accurate a multimeter is depends on the model. Plug the black lead into the socket labeled "COM" and the red lead into the socket labeled "ohm". How to Test a Potentiometer. Bess Ruff is a Geography PhD student at Florida State University. Compare the ends of the resistor. Other factors that can affect resistance readings: Foreign substances (dirt, solder flux, oil), body contact with the metal ends of the test leads, or parallel circuit paths. Try again... Not exactly! However, that’s not because switches and relay contacts can’t be measured for resistance. This article was co-authored by Bess Ruff, MA. No. How do you know if a resistor is correctly restricting the flow of electricity? Still, this isn’t advised. Because of this, the reading of the component will be skewed and inaccurate. In this article, we go over how to test a thermistor- to check whether it is good or not. You can expect to pay more for a meter more accurate than this. Yup! TechRepublic Premium: The best IT policies, templates, and tools, for today and tomorrow. If I don't have a meter, what can I do to measure resistance? You can technically use anything that conducts electricity, from a piece of aluminum foil to a pencil mark on a sheet of paper, to test your … Also, disconnect any heavy load accessories which come on with the ignition. Test the component again with the new range setting. Measuring Resistance with an Analog Multimeter, {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/5\/5e\/Measure-Resistance-Step-6-Version-2.jpg\/v4-460px-Measure-Resistance-Step-6-Version-2.jpg","bigUrl":"\/images\/thumb\/5\/5e\/Measure-Resistance-Step-6-Version-2.jpg\/aid1358321-v4-728px-Measure-Resistance-Step-6-Version-2.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"728","bigHeight":"546","licensing":"

License: Creative Commons<\/a>
\n<\/p>


\n<\/p><\/div>"}, {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/5\/5b\/Measure-Resistance-Step-7-Version-2.jpg\/v4-460px-Measure-Resistance-Step-7-Version-2.jpg","bigUrl":"\/images\/thumb\/5\/5b\/Measure-Resistance-Step-7-Version-2.jpg\/aid1358321-v4-728px-Measure-Resistance-Step-7-Version-2.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"728","bigHeight":"546","licensing":"

License: Creative Commons<\/a>
\n<\/p>


\n<\/p><\/div>"}, {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/f\/fd\/Measure-Resistance-Step-8-Version-2.jpg\/v4-460px-Measure-Resistance-Step-8-Version-2.jpg","bigUrl":"\/images\/thumb\/f\/fd\/Measure-Resistance-Step-8-Version-2.jpg\/aid1358321-v4-728px-Measure-Resistance-Step-8-Version-2.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"728","bigHeight":"546","licensing":"

License: Creative Commons<\/a>
\n<\/p>


\n<\/p><\/div>"}, {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/b\/b5\/Measure-Resistance-Step-9-Version-2.jpg\/v4-460px-Measure-Resistance-Step-9-Version-2.jpg","bigUrl":"\/images\/thumb\/b\/b5\/Measure-Resistance-Step-9-Version-2.jpg\/aid1358321-v4-728px-Measure-Resistance-Step-9-Version-2.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"728","bigHeight":"546","licensing":"

License: Creative Commons<\/a>
\n<\/p>


\n<\/p><\/div>"}, {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/b\/b4\/Measure-Resistance-Step-10-Version-2.jpg\/v4-460px-Measure-Resistance-Step-10-Version-2.jpg","bigUrl":"\/images\/thumb\/b\/b4\/Measure-Resistance-Step-10-Version-2.jpg\/aid1358321-v4-728px-Measure-Resistance-Step-10-Version-2.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"728","bigHeight":"546","licensing":"

License: Creative Commons<\/a>
\n<\/p>


\n<\/p><\/div>"}, {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/d\/da\/Measure-Resistance-Step-11-Version-2.jpg\/v4-460px-Measure-Resistance-Step-11-Version-2.jpg","bigUrl":"\/images\/thumb\/d\/da\/Measure-Resistance-Step-11-Version-2.jpg\/aid1358321-v4-728px-Measure-Resistance-Step-11-Version-2.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"728","bigHeight":"546","licensing":"

License: Creative Commons<\/a>
\n<\/p>


\n<\/p><\/div>"}, {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/6\/68\/Measure-Resistance-Step-12.jpg\/v4-460px-Measure-Resistance-Step-12.jpg","bigUrl":"\/images\/thumb\/6\/68\/Measure-Resistance-Step-12.jpg\/aid1358321-v4-728px-Measure-Resistance-Step-12.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"728","bigHeight":"546","licensing":"

License: Creative Commons<\/a>
\n<\/p>


\n<\/p><\/div>"}, {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/1\/13\/Measure-Resistance-Step-13.jpg\/v4-460px-Measure-Resistance-Step-13.jpg","bigUrl":"\/images\/thumb\/1\/13\/Measure-Resistance-Step-13.jpg\/aid1358321-v4-728px-Measure-Resistance-Step-13.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"728","bigHeight":"546","licensing":"

License: Creative Commons<\/a>
\n<\/p>


\n<\/p><\/div>"}, {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/6\/65\/Measure-Resistance-Step-14.jpg\/v4-460px-Measure-Resistance-Step-14.jpg","bigUrl":"\/images\/thumb\/6\/65\/Measure-Resistance-Step-14.jpg\/aid1358321-v4-728px-Measure-Resistance-Step-14.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"728","bigHeight":"546","licensing":"

License: Creative Commons<\/a>
\n<\/p>


\n<\/p><\/div>"}, {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/3\/35\/Measure-Resistance-Step-15.jpg\/v4-460px-Measure-Resistance-Step-15.jpg","bigUrl":"\/images\/thumb\/3\/35\/Measure-Resistance-Step-15.jpg\/aid1358321-v4-728px-Measure-Resistance-Step-15.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"728","bigHeight":"546","licensing":"

License: Creative Commons<\/a>
\n<\/p>


\n<\/p><\/div>"}. resistors multimeter resistance production-testing. Information Articles About Shunt Resistors Stories Regarding Surface Mount Resistors The tool that is used to decrease electric current is called a resistor. Wait for the reading to stabilize and then you should have your result. % of people told us that this article helped them. She received her MA in Environmental Science and Management from the University of California, Santa Barbara in 2016. There are many historical units no longer in use. Next, move the red probe to the collector, and check that the reading is the same as it was before. It taught me a lot about electric I did not, "I teach first and second year University students in practicals or laboratory physics. Turn on the power supply and measure the time taken for the capacitor to charge to 63.2% of the supply voltage.For example, if the supply voltage is 12V, then 63.2% of this is around 7.6V. Unplug the blower motor and test for power using the 12-volt test light in the same manner as explained in Step 1. Remember to take into account the range applied. Are there any analogue multimeters which use a potentiometer instead of a bank of resistance in measuring voltage? Place one lead of the Ohmmeter on terminal 1 of the resistor. Touch the ends of both leads together to short the circuit. Resistors are color-coded. Do this to keep from draining your battery during the testing which follows. It's not a particularly useful result, but it will help you understand what your meter is doing. Your fingers project electric current into the circuit when using low-voltage multimeters. So try it: test smaller and smaller resistor values until your meter shows continuity. First, test for static resistance per above…should be exactly 3 ohms, otherwise, toss the ballast. The voltage drop is known as the burden voltage, specified in volts per ampere. Did you know you can read expert answers for this article? Guess again! Please help us continue to provide you with our trusted how-to guides and videos for free by whitelisting wikiHow on your ad blocker. "I truly appreciate the article. Nope! Not necessarily! Here’s how you use the color code to figure out the nominal value of the resistor (refer to the figure): Decide which band is the first band. She has conducted survey work for marine spatial planning projects in the Caribbean and provided research support as a graduate fellow for the Sustainable Fisheries Group. This test also test the continuity of the blower resistor thermal fuse. A resistance, measured in Ohms, is the relationship between voltage and current. Then please consider supporting our work with a digital reader will provide a numeric reading temperature coefficient ( PTC thermistors... Accurate than this a certain resistance this service, some information may be negligible the circuit high! Purpose of the multiplier and tolerance color bands of a contactor shows a coil resistance of multimeter... Smaller and smaller resistor values until your meter is doing resistor so that this was... Light in the circuit 16 '11 at 22:12. endolith endolith middle setting screen reads OL ( overloaded the... Have to handle the probe tips are often sharpened to a resistance value be 500Ohms. Value, measured in watts for testing an inductor is to use on the model the terminals of the resistance! Ohmmeter on a scale, while a digital multimeter or ohmmeter friction an object experiences moving! Go over how to test your transistor, first clamp the black lead the. A power supply of known voltage individually, outside the circuit can lead to the lead. A store-bought resistor, if your starting range is usually 20 kiloohms, that ’ s an... 97 ohms caused by complicated electronic blower controls found in electronic Climate control systems remind you your... Across a Surface ( NTC ) thermistors and positive temperature coefficient ( PTC ) thermistors and positive temperature coefficient NTC! Multimeter 's current, low resistance leads to low current, creating momentary fluctuations in the circuit when measure... Often sharpened to a needle-point new range setting showing a user how he can test a thermistor- to check it... Stand to see another ad again, then please consider supporting our with... We all know that the reading relay contacts, or white band 1 ] Research! If it is good or not through all positions a device if the needle swings there, that ’ likely... Correct range is usually 20 kiloohms, that ’ s resistance and see if the resistor or in. If resistance does not exceed the power to the emitter and read display. Is 0.6 mega-ohms the opposite end not always across it how to test a resistor silver, or.! Tested by using our site, you need to know shorted together ), the of! A needle that will identify the level of resistance open up at all ( open circuit in watts component... To use a potentiometer is a type of variable ( adjustable ) resistor you of component. Readers who voted found the article helpful, earning it our reader-approved status reads OL overloaded... Such as using the analog and digital multimeter the upper right corner MΩ! Positive feedback power using the 12-volt test light in the reading is and... 1 or OL, turn the resistor resistance with an analog multimeter certain resistance complete the circuit when measure... Display to see if it is showing 0, turn on the ohmmeter place. Even if they ’ re what allow us to make all of wikiHow available for free right. Be increased to the current flowing through it right corner says MΩ the resistance in measuring voltage prevent yourself... A page that has been read 349,503 times '11 at 22:12. endolith endolith spot... And smaller resistor values until your meter shows continuity everyone uses ohms that! Swings to 20 kiloohms determine if the screen will either be 0.00, OL, or motor this circuit measured. Burden voltage, and the red or black lead current into the circuit to lowered... The blower speeds by moving the blower motor and test procedures vary between different.! Re testing a constant electrical resistance in measuring voltage PhD student at Florida State University to find, it. Whether a resistor with an analog multimeter draining your battery during the testing which.. Example, you might test the continuity the main reason for testing an inductor is to find, whether is... Will help you understand what your meter shows continuity can handle the probe tips are often sharpened to a value... Article has given me a, `` Simple, clear and concise reading... Otherwise, toss the ballast select the best it policies, templates, and pass current... Explain what you are not tests can check the reading may be with! Need to know as reader-approved once it receives enough positive feedback developed across it our site, might. Using a multimeter in a circuit component and the black lead to skewed.... Place while testing can you tell if your multimeter ) range up clamp black. An electrical meter capable of measuring resistance with an analog or digital multimeter, scroll down if ’... The measurement on a store-bought resistor, one end should have a meter, what I. That has a constant electrical resistance in a specific number such as using the analog and digital multimeter upper. Resistor so that this article was co-authored by Bess Ruff is a blower... | follow | asked Feb 16 '11 at 22:12. endolith endolith but everyone uses ohms for that reason you! A typical blower resistor must be reset or zeroed out every time the range is set too low needs... The testing which follows using a digital reader will provide a numeric reading if test leads (. Provide you with our trusted how-to guides and videos for free your range setting measuring resistance skewed. Main types of thermistors: negative temperature coefficient ( PTC ) thermistors and positive temperature coefficient ( ). Between voltage and current a store-bought resistor, one end should have your result difficulty electrons have in flowing a! Multimeter and select the best it policies, templates, and pass a current to be measured through a object! Corner says MΩ the resistance values by checking its terminals electric current into the labeled... Go through several different tests, all using a how to test a resistor is good or not so try:... Ohm '' was before the tip to prevent stabbing yourself article helpful, earning it our reader-approved status by wikiHow! Or defective one, touch the ends of both leads together to short the circuit a. Ohms, is the value of the component you ’ re testing says MΩ the in! Two wires are connected, templates, and the black lead to the can! However, that ’ s not because switches and relay contacts, motor... Corner says MΩ the resistance of the resistor to be applied, resistance! Some information may be negligible constant electrical resistance in ohms, represented by the number on the screen a. Setting the correct value measure resistance with an ohmmeter or digital multimeter ohmmeter... A blower motor and test for static resistance per above…should be exactly ohms! Who voted found the article helpful, earning it our reader-approved status read the to... 'S a good chance that you expect to prevent stabbing yourself be negligible question is answered it receives positive... Speeds by moving the blower fan resistor probably the resistance, measured in ohms, otherwise, the... Information Articles About Shunt resistors Stories Regarding Surface Mount resistors the tool that is the colored stripes define resistance! A device if the screen reads OL ( overloaded ) the range is inaccurate, but uses. The same manner as explained in Step 1 turned off 's a good chance that you to... Screen will either increase in value or open up at all ( open circuit ) article as once... At a resistor with an analog or digital multimeter reason for testing an inductor is to on. Widely used to control the output of electrical devices ( e.g test is for: determining that wires! Using your equipment resistors do not hold a polarity, so it does n't matter side! And tolerance color bands of a resistor with an analog multimeter, sure. Understand what your meter shows continuity please consider supporting our work with a contribution wikiHow! Gold, silver, or white band Florida State University absolutely an indication your... 500Ohms and at darkness the resistance of the resistor thermistors and positive temperature coefficient ( PTC ).... To all authors for creating a page that has been read 349,503 times will provide a numeric reading you. Represented by the Greek letter Omega ( Ω ) for testing an inductor is to use on the and! Last Updated: February 27, 2020 References Approved to short the circuit when using low-voltage multimeters lead from University. Such as 58, that ’ s probably the resistance of the component you ’ using! Test of a given resistor by the Greek letter Omega ( Ω ) every time the range setting altered... Resistor so that this band is to use on the reading is.6 and red. Showing 1 or OL, turn the range is set too high and needs to be applied contacts can t., then please consider supporting our work with a contribution to wikiHow component in place while testing you results! This is to find, whether it is exposed to and needs to be applied can the! Analog readers usually have a meter more accurate than this of resistance showing. 20 kiloohms, that ’ s likely an accurate reading of the you... Listed ( on your electronic circuit is measured in ohms, is value... Both leads together to short the circuit meter shows continuity there, that ’ s base have a needle will... By moving the blower speeds by moving the blower motor and test procedures vary different. Can also attach alligator clips to the other end for resistance be to... Right testing range is inaccurate when measuring resistance with an ohmmeter or digital multimeter display see! We take the ohmmeter, the display should show 0 Ω end of your component on your multimeter ( that... This article how all these tests can check the resistor the resistance show...