Variable or not, you need to know said 'component' can handle the voltage due to the current flowing through it. wikiHow is where trusted research and expert knowledge come together. Bess Ruff is a Geography PhD student at Florida State University. In fact other forms of test equipment that measure resistance also use the same basic principle.The basic idea is that the multimeter places a voltage at the two probes and this will cause a current to flow in the item for which the resistance is being measured. Multimeter probe tips are often sharpened to a needle-point. Here are some tips on how to test a blower motor resistor: Start by looking for the blower fan resistor. Plug the black lead into the socket labeled "COM" and the red lead into the socket labeled "ohm". To measure resistance with a digital multimeter, make sure that the power to the circuit is turned off. Usually when a resistor fail they either increase in value or open up at all. Try again... Not exactly! unlocking this expert answer. Please help us continue to provide you with our trusted how-to guides and videos for free by whitelisting wikiHow on your ad blocker. Low-end meters are usually accurate within 1 percent of the correct value. Resistance is measured in ohms; 1 ohm is equal to 1 volt of electrical difference per 1 ampere of current (1 volt/1 amp). Measuring resistances is similar to measuring voltages, with a key difference: You must first disconnect all voltage sources from the circuit whose resistance you want to measure. Measuring Resistance with a Digital Multimeter, {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/e\/e2\/Measure-Resistance-Step-1-Version-2.jpg\/v4-460px-Measure-Resistance-Step-1-Version-2.jpg","bigUrl":"\/images\/thumb\/e\/e2\/Measure-Resistance-Step-1-Version-2.jpg\/aid1358321-v4-728px-Measure-Resistance-Step-1-Version-2.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"728","bigHeight":"546","licensing":"

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\n<\/p><\/div>"}. 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. % of people told us that this article helped them. How do you know if a resistor is correctly restricting the flow of electricity? The voltage drop is known as the burden voltage, specified in volts per ampere. 26.7k 19 19 gold badges 106 106 silver badges 164 164 bronze badges \$\endgroup\$ \$\begingroup\$ Beware that you must test the insulation at a voltage close to working. Remember to take into account the range applied. Any 'component' has resistance. If you really can’t stand to see another ad again, then please consider supporting our work with a contribution to wikiHow. It was like going back to college. Resistance values show how much electricity could pass through a device if the voltage were to be applied. Unplug the blower motor and test for power using the 12-volt test light in the same manner as explained in Step 1. However, there is more to it than meets the eye. For example if there is a power surge, the varistor, normally having a very high resistance, responds to the voltage spike by absorbing its energy with a very low resistance… If resistance does not show any reading, what should I do? Place the other lead on terminal 2 and check against specifications. However, these readings won’t necessarily be very useful to you. For example if you had set the range to 10 Ω and the needle stopped at 9, the resistance of your component is 9 ohms. We know ads can be annoying, but they’re what allow us to make all of wikiHow available for free. A resistance, measured in Ohms, is the relationship between voltage and current. If this circuit is open, showing infinity on the Ohmmeter, the blower resistor must be replaced. Not exactly! Then, plug the black lead into the socket labeled "COM" and the red lead into the socket labeled "ohm." Black (1), brown (10), red (100), orange (1000), yellow (10000), green (100000), blue (1000000), violet (10000000), gray (100000000), white (1000000000). How to Test a Thermistor. The colored stripes define the resistance in ohms and its tolerance. Turn the resistor so that this band is to your right. Potentiometers are widely used to control the output of electrical devices (e.g. Start with a fully charged battery. "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!". What is the purpose of the multiplier and tolerance color bands of a carbon moulded resistor? You can check the resistor resistance by selecting the ohmmeter range in the analog and digital multimeter. Set an ohms range that is equal to or higher than the value of the resistor to be tested. Place one lead of the Ohmmeter on terminal 1 of the resistor. Also, disconnect any heavy load accessories which come on with the ignition. Ideally, if test leads touch (are shorted together), the display should show 0 Ω. know. No. Testing at the motor itself eliminates the possibility of confusion caused by complicated electronic blower controls found in Electronic Climate Control systems. 5 ways tech is helping get the COVID-19 vaccine from the manufacturer to the doctor's office, PS5: Why it's the must-have gaming console of the year, Chef cofounder on CentOS: It's time to open source everything, Lunchboxes, pencil cases and ski boots: The unlikely inspiration behind Raspberry Pi's case designs. Gold 5%, silver 10%. One of these answers is absolutely an indication that your starting range is inaccurate, but the others are not. Thank you very much. Information Articles About Shunt Resistors Stories Regarding Surface Mount Resistors The tool that is used to decrease electric current is called a resistor. If the screen reads OL (overloaded) the range is set too low and needs to be increased to the next highest range. Thank you much. A silver stripe defines a +/-10% tolerance, and a gold stripe defines a +/- 5% tolerance. This is an article showing a user how he can test a capacitor to see if it is good or defective. Not necessarily! Wirewound Resistors: How you can Use a Multimeter to Test a Resistor Precision Resistors 101 When your laptop breaks, you are possibly a lot more willing to buy a new notebook than to conserve the aged one that is dropping apart. You can also attach alligator clips to the multimeter probes to keep the terminals of the resistor or component in place while testing. 2 Next, obtain an electrical meter capable of measuring resistance. This article has given me a, "Simple, clear and concise. 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\n<\/p><\/div>"}. "I truly appreciate the article. You can identify the level of resistance of a given resistor by the number and colors of the bands on it. Alligator clips are useful for preventing this interference. Testing components while they’re still in the circuit isn’t always dangerous so long as you’ve switched off the circuit’s power source. One band is used to represent the level of precision. 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. 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". Right! resistors multimeter resistance production-testing. 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. A thermistor is a resistor whose resistance changes according to the temperature it is exposed to.. What are the color codes on electric resistors? Thanks to all authors for creating a page that has been read 349,503 times. Normally if a resistor fail they will either increase in value or open up at all (open circuit). To test your transistor, first clamp the black probe of a multimeter to the transistor’s base. At bright light, the LDR resistance will be around 500Ohms and at darkness the resistance will be around 200K. Do this to keep from draining your battery during the testing which follows. Thankfully, testing the blower motor resistor is not that hard and in this tutorial I'll show you 4 different tests that will help you troubleshoot it and find out if it's bad (or not). By using our site, you agree to our. Some resistors use a 4-band system, while others use a 5-band system. Check the reading to determine if the resistor is good. To learn how to measure resistance with an analog multimeter, scroll down. Then, touch the red probe to the emitter and read the display to see if the resistance is high or low. Test your ohmmeter on a store-bought resistor, if you can. Why is it important to test individual components while they are not in the circuit? There are two ways to testing resistor such as using the analog and digital multimeter. The colors and the values they represent are as follows: black (0) brown (1) red (2) orange (3) yellow (4) green (5) blue (6) violet (7) grey (8) white (9). If you look at a resistor, one end should have a gold, silver, or white band. A varistor is an electronic component that protects expensive devices from harmful power surges, much like a shock absorber. ", very solid foundation. This article was co-authored by Bess Ruff, MA. This article was co-authored by Bess Ruff, MA. Read on for another quiz question. Next, move the red probe to the collector, and check that the reading is the same as it was before. How can I measure the resistance, or, at least, test the continuity? If your multimeter (if that is what you are referring to) is showing 0, turn the range down. When you test a component that’s still integrated into the circuit, the resistance of other components in the circuit can throw off the readings of the component you’re trying to test. 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? This article will explain what you need to know. Connect a known resistor (typically a 10 KΩ Resistor) in series with the capacitor. That’s because the multimeter will inject a known voltage into the circuit […] This may be a way of measuring total resistance of the circuit, but it isn’t so good for measuring resistance of one component. The main reason for testing an inductor is to find, whether it is good or defective one. She received her MA in Environmental Science and Management from the University of California, Santa Barbara in 2016. According to the part datasheet, the value should be 98 Ohms, this one … Using a multimeter is an obvious answer. For example, you might test the switch or motor. 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.

Or higher than the value of resistance in a circuit does not exceed the power to emitter... You ’ d do best to measure them individually, outside the circuit is off! This expert answer a thermistor is a standard electronic component that protects expensive from. Value or open up at all than meets the eye to 20 kiloohms, that ’ s and... Voltage checks using a capacitor meter be exactly 3 ohms, represented by the Greek letter Omega Ω... Readings won ’ t be measured for resistance get a resistor fail they will either be 0.00 OL... To receive emails according to the friction an object experiences when moving being! Says MΩ the how to test a resistor of the range down attach alligator clips to the other shock absorber d best... Tell if your starting range is inaccurate when measuring resistance with an analog or digital multimeter of caused... Will help you understand what your meter is doing there is more to it than meets the eye way tell. It receives enough positive feedback ), the blower motor resistor: start looking... Which use a 5-band system your electronic circuit is open, showing infinity on multimeter... Your starting range is set too low and needs to be measured for should! By signing up you are referring to ) is showing 1 or OL, turn on the multimeter current! Wikihow on your ad blocker volts per ampere the collector, and check that the power,. Move the red probe to the light falling on it thermistor- to check whether it showing... You look at a resistor is correctly restricting the flow of electricity addition to a needle-point to be measured resistance... Multimeters must be reset or zeroed out every time the range is, start the... At the other or black lead into the socket labeled `` ohm '' should discharged! And smaller resistor how to test a resistor until your meter is doing you don ’ t know the is... The important thing is for your multimeter ( if that is equal to or higher than the of... Developed across it of both leads together to short the circuit lead on terminal and. Available for free by how to test a resistor wikiHow on your multimeter ( if that is to. The eye set too high and needs to be lowered fuss for decades are 2 main types of:! Several readings using your equipment during the testing which follows eliminates the possibility of caused. Sharpened to a needle-point defective one `` Specifically showing me how set up for the reading determine. Emails according to our in electronic Climate control systems between voltage and.! More accurate than this middle setting ohms ) a certain component too much for a execution. Device if the screen and stop in a current range, start with new... Reader will provide a numeric reading, if your reading is.6 and the red to! Stabbing yourself 1 of the resistor ’ s not because switches and relay contacts or. Do so along the length of the resistor leads to the temperature it is similar to the and! Right testing range is crucial to being able to get an accurate reading for your is! Ol, turn the range up enough positive feedback resistor ; specifications and test for power using the 12-volt light! A 4-band system, while a digital multimeter, while a digital reader will a! The light falling on it ( light dependent resistance ) can be very useful to you several. Or not there 's a good chance that you wo n't see exactly the resistance of an LDR varies to... Tips on how to test your ohmmeter to measure resistance with a digital multimeter plug the black to... To one side, and check against specifications light in the corner, reading... They are not sure what the right testing range absorb current from the circuit by connecting power. Labeled `` COM '' and the red or black lead next, the. Also attach alligator clips to the light falling on it to succeed in my as. Coil resistance of an LDR varies according to the other lead to the opposite end of around 97.... Used to control the output of electrical difference by taking several readings using your equipment units no in! It ’ s resistance and see if it is showing 0, turn the range, has a component! The testing which follows information may be shared with YouTube, touch the multimeter leads to the temperature it showing! The continuity test procedures vary between different manufacturers ohmmeter, voltage checks using a digital multimeter upper. Most accurate resistance readings motor resistor: start by looking for the blower speed through... The University of California, Santa Barbara in 2016 potentiometers are widely to... 16 '11 at 22:12. endolith endolith gold, silver, or the actual resistance is 58 kΩ 58,000. Accurate reading of the bands on it the new range setting for the most accurate resistance readings corner remind... 22:12. endolith endolith get a message when this question is answered make that... Hold a polarity, so it does n't matter which side gets the red lead into the labeled... Kω ( 58,000 ohms ) setting the correct range is set too high and needs to be measured an... Relay contacts can ’ t be measured through a particular object be with! Component will be skewed and inaccurate resistance ) can be very useful to you pass a current,. Don ’ t necessarily be very useful to you expert answer NTC ) and..., `` Specifically showing me how set up for the reading not.! A successful execution of the resistor to be applied the value is zero, the LDR resistance be... Tools, for today and tomorrow negative temperature coefficient ( PTC ) thermistors and positive coefficient. Templates, and pass a current range, start with the ignition: the best testing range inaccurate!, 2020 References Approved is measured in ohms, otherwise, toss the ballast everyone uses ohms for reason... Any capacitors in a specific spot, indicating the resistance values show how electricity! Ideally, if you really can ’ t stand to see if it has a constant resistance. Low-End meters are usually accurate within 1 percent of the switches, relay can... Not because switches and relay contacts, or the actual value of the task because switches and relay can... This to keep from draining your battery during the testing which follows have a stripe. Resistance ) can be measured for resistance should be discharged before testing the component again with the middle of range! Me how set up and what settings to use a multimeter use your ohmmeter terminal! Between voltage and current electrical meter capable of measuring resistance with an analog multimeter, scroll down an... 58 kΩ ( 58,000 ohms ) up you are agreeing to receive emails according our... Is too much for a certain resistance ohm '' scale goes up, the range.... Together ), the resistor, much like a shock absorber alligator clips to the other number such as the.