Follow the following step to check if capacitor is bad or good. Take the MESR-100 and turn it on. Take your capacitor and discharge it properly through resistance material. Discharging a capacitor can be done by shorting the legs of the capacitor by any high resistance substance available to you. Connect the discharged capacitor to the ESR meter.
The first method is a visual inspection. The second method is using a capacitance or multimeter to verify its capacitance value with a given tolerance. The last one is by measuring the ESR value of the capacitor. Some of the above methods are applicable for off and in circuit testing as well.
For a good Capacitor, every attempt of the test should show a similar result on the display. If in the further tests there is no change in the resistance, then the capacitor should be replaced as it is a dead one. At first, the Capacitor must be disconnected from the circuit board and then it should be discharged completely.
To test a capacitor’s functionality, follow these steps using the capacitance mode on the multimeter 1. Detach the capacitor from the circuit in which it is incorporated. 2. Check the capacitance value indicated on the exterior of the capacitor. Capacitance is measured in farads (abbreviated as “F”).
A motor with a defective capacitor either hums before starting or starts with a clearly audible hum. These are clear signs of a loss of capacity and thus a defective capacitor. You should be very careful with this type of test as there is a great risk of injury. Above all, never test saws or lawnmowers, in this way.
ESR stand for equivalent series resistance. What happens to a bad capacitor is that its ESR value changes. The change in ESR is totally helpful when determining with 100% sure if the capacitor is bad or good. Usually a bad capacitor can doge the visual inspection method as well the capacitance measurement method.