A capacitor can be tested to know its current status. For example, the condition, strength and the remaining capacity of a capacitor could be determined. Capacitor provides initial electric charges to the electrical appliances. Capacitor can be tested with the help of a basic analogue ohm meter. The analogue ohm meter has a needle to indicate the readings. The task could be a bit difficult for an amateur. This is due to the fact that capacitor may give an electric shock even if it not connected to an active electrical source. Hence, a risk of shock is always there.
Since capacitor is the power house unit of electrical appliances, they can give you bad time if you touch the terminals of a charged capacitor. To avoid such mishaps, always discharge the capacitor before testing it. You can discharge it through a screw driver which has an insulated handle. Touch both the probes of the capacitor on the metal end of the screw driver and it discharges along with a spark.
Now, make way for the ohm meter. Plug the red lead into the connector indicating ‘ohm’ and the black lead into the connector indicating ‘com’. Next, switch on the instrument. In some cases, you have to manually switch the meter to ohm position.
Next, place the red lead into the ohm connector and the black one in the ‘com’ connector. In the reading area of the meter, the extreme right indicates zero ohms. The far left represents infinite value of resistance. Touch the metal ends of both the leads and modify the settings to get ‘zero’ on the ohm indicator.
Now, make contact between the terminals of capacitor and the ohm meter leads. If the needle moves towards the zero ohms and then back to the infinite position, then it indicates that the capacitor is in good condition. The uniform movement of needle indicates that capacitor is correctly charging and discharging.
Next, reverse the position of the leads on the capacitor terminals. If no difference occurs then it is ok. If however the needle deflects towards the right (zero ohm) and does not come back to left (infinity) then it refers to a shorted capacitor.
In case the needle of the ohm meter never changes its position, a wide-open or an internal break to the capacitor could be in sight. This indicates that the capacitor needs to be replaced with a newer one.
Always perform testing carefully as the charged capacitor can prove hazardous.
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