Thursday, September 23, 2010
*** PLEASE READ: This is another way to measure the value of a capacitor. I have a beter method in another video, but this is one often mentioned due to that a signal generator (ie sine wave frequency) is not needed. For safety, discharge any capacitor before working with it. Use some resistance (lower than the resistance of air) value across its terminals. Some capacitors are "polarized" and can only be charged with the positive voltage connected to the (+) terminal, and the negative voltage connected to the (-) terminal, otherwise it will probably explode. This method here will work good for higher value capacitors, say 500uF up and up. Choose a resistor so that the capacitor can discharge reasonably slow, for greater accuracy in the results, hence a larger resistor, perhaps 1K to 10K. The smaller the capacitor being measured, the greater the resistance needed so that you can visually see the voltage levels and for accuracy since a small capacitor discharges very rapidly. The problem then will be that that the internal resistance of the meter starts to have greater effect on the overall (ie parallel) resistance in the test circuit. Here is a stopwatch timer on this webpage: www.online-stopwatch.com A good capacitor will hold its voltage for quite a time. A bad one has "leakage" (or current flow) through the dielectric material seperating the plates of the capacitor. It is possible to refurbish a capacitor a bit using a "voltage treatment"... bring the voltage up across ...
http://www.youtube.com/watch?v=s2iHsOldkbc&hl=en
