How to test a capacitor with a multimeter in a circuit?
Answers
what is a multi meter I don't know my friend
you can tell me what is a multi meter
Method 1 Checking a Capacitor using Multimeter with Capacitance Setting
This is one of the easiest, quickest and accurate way to test a capacitor. For this, we need a Digital Multimeter with Capacitance Meter feature. Most of the mid and high end Digital Multimeters include this functionality.
The capacitance meter on the digital multimeters often display the capacitance of the Capacitor but few meters display other parameters like ESR, leakage, etc.
In order to test a capacitor using Digital Multimeter with Capacitance Meter, the following steps can be followed.
Disconnect the Capacitor from the circuit board and discharge it completely.
If the capacitor ratings are visible on its body, make a note of it. Usually, the capacitance in Farads (often micro Farads) is printed on the body along with the voltage ratings.
In the Digital Multimeter, set the knob to capacitance settings.
Connect the multimeter probes to the terminals of the capacitor. In case of a polarized capacitor, connect the red probe with the positive terminal of the capacitor (generally, the longer lead) and the black probe to the negative terminal. In case of non – polarized capacitor, connect it either way as they do not have polarity.
Now, check the readings on the Digital Multimeter. If the multimeter readings are closer to the actual values (mentioned on the capacitor), then the capacitor can be considered as a good capacitor.
If the difference between the actual value and the measured reading is significantly large (or sometimes zero), then you should replace the capacitor as it is a dead one.
Using this method, capacitors ranging from few nano Farads to few hundreds of micro Farads of Capacitances can be measured.
Method 1
Method 2 Checking a Capacitor using Multimeter without Capacitance Setting
Most of the low end and cheap Digital Multimeters do not include Capacitance Meter or Capacitance Settings. Even with these Multimeters, we can test a Capacitor.
Remove the Capacitor from the circuit or board and make sure it is completely discharged.
Set the Multimeter to measure resistance i.e. set the knob to Ohm or Resistance Settings. If there are multiple ranges of resistance measurement, select a higher range (often 20 KΩ to 200 KΩ).
Connect the multimeter probes to the leads of the capacitor (red to positive and black to negative in case of polarized capacitors).
The Digital Multimeter will show a reading of resistance on the display and soon will display the resistance of an open circuit (infinity). Note down the reading that was displayed for that short period.
Disconnect the capacitor from the multimeter and repeat the test several times.
Every attempt of the test should show similar result on the display for a good capacitor.
If there is no change in the resistance in the further tests, the capacitor is dead.
This method of testing the capacitor might not be accurate but can differentiate between a good and bad capacitors. This method also doesn’t give the capacitance of the capacitor.
Method 2