Electronics circuits use capacitors to store voltage. Every electrical and electronics circuit needs a capacitor. Troubleshooting an electronic circuit may involve testing a capacitor. There are multiple ways to test a capacitor like digital multimeter, voltage meter, and ohmmeter.
Before testing a capacitor, make sure to disconnect the capacitor from the circuit. And short the terminals of the capacitor using a resistor of at least 1k. Try to avoid contact with the terminals during the process. Otherwise, the charge on the capacitor may cause you an electric shock.
Testing a Capacitor with a Multimeter
Testing a capacitor with a multimeter is the easiest and quickest way. The required instrument of the test is a digital multimeter with a capacitance testing feature.
- Remove the capacitor from the circuit and short the terminal to avoid and electric shocks.
- Set the digital multimeter to capacitance setting.
- Connect the probes of the multimeter to the capacitor terminals.
- For the polarized capacitor, connect red prob to positive and black to negative terminal of the capacitor.
- For nonpolarized, you can connect it in either way.
- Now, look at the screen of the digital multimeter to read the capacitance of the capacitor.
- You can compare the reading with the rating printed on the capacitor. If they are close, the capacitor is good.
- In case of large variation, the capacitor may be considered a bad capacitor.
- A bad capacitor can be replaced with a new similar rating capacitor.
Testing a Capacitor with Voltmeter
Testing a capacitor with a voltmeter can give you an idea if the capacitor is good or bad. For this method, you need a voltmeter and a power supply. The voltage of the power supply must be less than that of the capacitor.
- Disconnect the capacitor from the circuit and discharge.
- Connect the capacitor to the power supply and charge it for at least 4 to 6 seconds.
- Make sure the voltage of the power supply is less than the printed voltage on the capacitor.
- Now disconnect the capacitor from the power supply.
- Do not touch or short the capacitor terminals.
- Connect the capacitor to the voltmeter.
- Read the voltmeter reading if it close to the power supply voltage or not.
- If it is close to the supply voltage the capacitor is good.
- If the reading much less the capacitor is bad.
- Always disconnect the capacitor from the circuit to test it.
- A digital multimeter may give you the exact capacitance of the capacitor.
- Testing a capacitor with a voltmeter may tell you if it good or bad capacitor.