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How to Test an MFD Capacitor

By Brandy Alexander
Now you can troubleshoot capacitors yourself.

Testing an MFD capacitor, otherwise identified as a uF or micro farad capacitor, is easy with the right tool. Over the course of their lives, capacitors often become corroded and no longer perform their intended purpose. With a common digital capacitance meter, you can quickly and effectively test whether or not your capacitor is functioning as labeled. If your electronic device has stopped working, testing the capacitors in it is a great place to start to troubleshoot it back to working order.

Connect the black, negative lead of your capacitance meter to the shorter of the two terminals on the capacitor. If the terminals are of the same length, then it is not polarized, and you can attach the negative lead to either of them.

Connect the positive red lead from the meter to the other of the two terminals on the capacitor.

Adjust the selector wheel on the meter to the next-highest maximum reading than the rating printed on the capacitor. For example, if your capacitor was labeled as 270 uF/MFD, and your meter had a setting for both 200 uF and 2000 uF, you will need to select 2000 uF to get an accurate reading.

Read the display screen on the meter. If the value stated is above or below 10 percent of the value printed on the capacitor, then the capacitor is in working condition. If the value on the meter's screen is more than 10 percent above or below the value printed on the capacitor, it is not working as it should, and should be replaced with a properly functioning replacement. For example if the meter read 450uF and the capacitor is labeled 470uF, it is good. But if the meter reads 200uF, and the capacitor is labeled 470uF, it is not working properly

 

Things You Will Need

  • Digital capacitance meter

About the Author

 

Brandy Alexander began writing professionally in 1993. She has years of experience as a professional of the English language employed with the "Cape Times" and "The Mercury." Alexander holds a master's degree in English literature from Stellenbosch University in South Africa.