Hello Zeromedia! Are you having trouble with your electronic devices? Capacitors are one of the most commonly replaced parts in electronics. They store electrical charge and act as filters, but they can go bad over time. In this article, we’ll show you how to test a capacitor to see if it’s working properly. Let’s get started!
- A digital multimeter
- A discharged capacitor
- A power source (such as a battery)
- A resistor (around 1k ohm)
- A soldering iron (if you need to remove the capacitor from the circuit)
Step 1 – Safety First
Before starting to test your capacitor, it’s important to discharge it. You don’t want to get a shock or damage the device. To discharge your capacitor, connect a resistor between its terminals and wait until the voltage is completely gone. You can also use a screwdriver with an insulated handle to short the capacitor’s terminals to discharge it.
Step 2 – Set Your Multimeter
Set your multimeter to the capacitance measurement option. Some multimeters may have a different symbol that indicates capacitance, such as the letter “C”. Make sure your multimeter has this option before starting.
Step 3 – Test Your Capacitor
With your capacitor discharged, connect the multimeter leads to the capacitor terminals. The positive lead should connect to the terminal with a “+” sign, while the negative lead should connect to the terminal with a “-“ sign. If you don’t see any markings on the capacitor, test the leads with your multimeter to find out which one is positive and negative.
Step 4 – Read the Multimeter
The multimeter will display the capacitance value of the capacitor. A perfectly working capacitor should show a value within 5% of the rated capacitance. If your capacitor is rated at 10 microfarads, it should read between 9.5 and 10.5 microfarads on the multimeter. If it reads far less than the rated capacitance value, then it’s likely faulty.
Step 5 – Check for Leakage
If your multimeter has a leakage measurement option, your next step is to check for leakage. Connect the positive and negative leads of your multimeter to each terminal of your capacitor, then slowly watch the reading over time. If the value on your meter increases quickly and never stabilizes, then your capacitor is leaking and needs to be replaced.
How to Test Capacitor in Circuit
Step 1 – Disconnect the Capacitor from the Circuit
If you can’t remove the capacitor from the circuit, you can test it in place. However, you’ll need to first disconnect the capacitor from the rest of the circuit. Use a soldering iron to remove one lead of the capacitor from the PCB, but make sure you remember which lead goes where.
Step 2 – Discharge the Capacitor
Discharge the capacitor as described in Step 1 above, then proceed with the next steps.
Step 3 – Multimeter Set Up
Set up your multimeter as described in Step 2 above. If the capacitor is still connected to other components, you have to be careful not to accidentally touch other parts of the circuit with the multimeter leads.
Step 4 – Check Capacitance
Check the capacitance as described in Step 3 above. If the capacitor is still within the acceptable range, then it’s not faulting. Otherwise, you have to replace it.
How to Test Non-Polarized Capacitors
Step 1 – Discharge the Capacitor
Discharge the capacitor as described earlier in this article to be safe.
Step 2 – Identify the Terminals
Non-polarized capacitors have two terminals of the same size, so it doesn’t matter which lead goes where. You can use any of the two terminals.
Step 3 – Multimeter Set Up
Set the multimeter as described earlier. Connect the multimeter leads to the non-polarized capacitor terminals.
Step 4 – Capacitance Reading
Check the capacitance reading in the same way as with the polarized capacitor. Non-polarized capacitors typically have a wider tolerance range of up to 20%, so make sure to refer to the datasheet for the specific requirements for your capacitor.
How to Test a Capacitor with a Multimeter and Battery
Step 1- Gather Materials
You will need a battery, a resistor, a multimeter, and of course, your capacitor.
Step 2 – Discharge the Capacitor
Discharge your capacitor as described earlier above.
Step 3 – Connect a Resistor to the Capacitor
Connect one side of the resistor to the negative terminal of the capacitor, and the other side of the resistor to the negative side of the battery. Connect the positive side of the battery to the positive terminal of the capacitor.
Step 4 – Monitor Voltage
With your multimeter set to DC voltage, monitor the voltage across the capacitor. The voltage should rise quickly and then gradually decrease as the capacitor charges up. If the voltage does not rise quickly, then the capacitor is faulty and needs to be replaced.
Step 5 – Check Polarity
If your capacitor is polarized, you’ll need to reverse the connections from the battery and repeat the test. Swap the negative wire of the battery with the positive wire of the capacitor and vice versa.
FAQ About Capacitors
|What happens if a capacitor fails?||If a capacitor fails, it can either short out, which could damage other components in the circuit, or it could open, which could lead to a loss of function in the device.|
|Can I replace a capacitor with a higher value?||It’s generally not a good idea to replace a capacitor with one that has a higher capacitance value than the original. Doing so could damage the rest of the circuit and the device.|
|Can a capacitor kill you?||Capacitors store energy and can deliver an electric shock. It’s important to discharge capacitors before handling them to avoid injury or death.|
|Can capacitors hold their charge forever?||No, capacitors will slowly disperse their charge over time. However, some capacitors can hold their charge for a few hours or even days before discharging completely.|
Testing a capacitor can seem daunting at first, but with the right tools and instructions, it’s actually quite simple. We hope this article has helped you understand how to test your capacitors and identify any faults. Remember to always prioritize safety when handling electronic components.