When was the last time you checked a capacitor? Although most electricians may eventually encounter capacitors in the course of their work, not all of them will be familiar with the process of testing such a component.
In many cases, a failed capacitor will leak electrolytic fluid, rendering it useless as a power source. The capacitor’s host device may suffer irreparable harm as a result. If this happens, you might need to replace the part or get it fixed by an expert.
This article will be useful if you are an electrician who wants to test a multimeter with another multimeter. There are various varieties of capacitors and various methods for evaluating them. Testing for ESR is the best option if you have the means to do so.
Contents
Capacitor Basics
In electronics, energy can be stored in the form of an electric charge in a capacitor. It’s usual to find them in electronic circuits where they store energy and release it when needed.
The amount of energy that can be stored in a capacitor is determined by its physical size and the circuit arrangement in play when electricity is passed through it to charge it from another section of the electronics infrastructure.
When a battery is plugged into a circuit and voltage is applied across both plates, electrons begin flowing from one to the other until one plate can no longer hold any more, at which point the entire cycle of charging and discharging begins again.
Capacitor Testing
Multimeter Ohmmeter Capacitor Test
Using the ohmmeter function of a multimeter, we will examine the process of testing a capacitor in this section. This quick quiz will only take a few seconds of your time.
Place one probe across both capacitor leads (any way works) and read the results. The next step is to enter the resistance values from left to right for each of the leads.
If there are issues, it’s probably because our capacitor is broken or needs maintenance before use. Caution should be exercised while inspecting capacitors of this type because they have the ability to overcharge and damage electrical components like lights if not properly inspected.
Ohmmeter Testing Capacitor Resistance
One way that energy can be stored is in an electric field, and one way that this is done is through a capacitor. It helps steady the power supply to sensitive equipment like computers and protects circuits from sudden voltage spikes.
The presence of a short circuit, indicated by a reading of near zero ohms across the capacitors, indicates that electricity is unable to pass through the component due to a flaw or deficiencies.
If you leave your laptop plugged into the charger overnight, the next time you need to use it, even if it’s just to temporarily offload any last bits of data before shutting down properly, you might find that everything goes dark immediately, and if enough heat has been generated by long exposure during charging cycles, smoke might start.
The Capacitance Setting of a Multimeter for Capacitor Testing
When the capacitor malfunctions, the circuit will not work. Putting two probes of a multimeter into contact with the leads of a mystery capacitor and switching the multimeter to the Capacitance setting is all that’s required for this check.
Customers who are using their equipment properly but still experiencing occasional problems due to factors beyond their control (such as dirty connections or faulty parts) are more likely to provide constructive feedback if they are made aware of the proper procedures for dealing with such situations.
It’s ideal for getting a reading that’s close to the capacitor’s rated capacitance. It is possible to get a slightly lower reading than the claimed capacity due to tolerance and the fact that (in the case of electrolytic capacitors) they can dry up with time.
Everything here is wonderful. If it’s not much lower, or if it’s not lower at all, what do your readings tell you? That would necessitate some sort of magical replacement.
In this scenario, measuring the amount of voltage it can handle is a good indicator of whether or not a capacitor needs to be replaced.
Voltmeter Testing Capacitor
There are a few checks you can do to make sure your capacitor is good to go. The voltage test is a quick and simple method that you’ve likely heard about before.
Different types of charges exist on the anode (positive) and the cathode (negative) in a battery (negative). By connecting the two halves together, for example, with jumper wires, you can harness the electrostatic attraction to create energy.
A capacitor’s proper operation can be verified by applying a charge and observing the resulting voltage at its terminals. The capacitor has kept its ability to store electricity between two terminals if the reading corresponds to what it was charged to.
However, if you don’t get this reading or the voltage isn’t as high as usual after charging, you should check your cap’s compatibility with your device before continuing.
The Capacitor Charging Process
By connecting DC voltage to the capacitor’s terminals, you can fill it up. For polarized capacitors, the polarity is critical (electrolytic).
If a polarized capacitor is involved, make sure the leads are correctly connected. The capacitor’s positive charge should be connected to its anode (the shorter end) and its negative charge to the ground (shorter). Charge is gradually using a lower voltage than it can safely manage; for example, use 9 volts with a capacitor that can safely handle 25 volts.
If you are not using a very large capacitor, you can check its voltage with a multimeter immediately after it has finished charging (which should only take a few seconds) and then reconnect it to the power supply. The initial reading should be close to 9 volts (or the input voltage).
If the voltage drops suddenly and suddenly reaches 0V, there is likely a problem with the capacitor.
For your cap to act in this way, it’s either been damaged before or broken. If you suspect this is the case with your electronics, you should swap out the offending part immediately.
Things to Consider
It is also possible to calculate the ideal capacitor by measuring the time it takes for the capacitor to discharge to around 36.8% of the applied voltage’s peak value.
Capacitor testing is a breeze and should be done regularly. Over time, they lose their capacity to store energy; therefore, regular checks are recommended.
Conclusion
Leaking electrolytic fluid renders a failed capacitor useless as a power source. If you can afford it, getting an ESR test is your best bet. Capacitors of this type can overcharge and cause damage to electrical components and should be inspected with care. When the ohmmeter reading across the capacitors is close to zero, it’s possible that a short circuit is present and the components need to be replaced. Simple as it may be, capacitors require routine testing.
It is recommended to check them on a regular basis because their energy-storing capacity decreases with age. Polarity is very important for polarized capacitors (electrolytic). It is estimated that the ideal capacitor can store up to 36.8 percent of the peak value of the applied voltage before discharging.
Content Summary
- In order to determine if a capacitor needs to be replaced or repaired, you will learn the fundamentals of doing so at the end of this article.
- Testing for ESR is the best option if you have the means to do so.
- Using the ohmmeter function of a multimeter, we will examine the process of testing a capacitor in this section.
- One way that energy can be stored is in an electric field, and one way that this is done is through a capacitor.
- It helps steady the power supply to sensitive equipment like computers and protects circuits from sudden voltage spikes.
- When the capacitor malfunctions, the circuit will not work.
- It’s ideal for getting a reading that’s close to the capacitor’s rated capacitance.
- In this scenario, measuring the amount of voltage it can handle is a good indicator of whether or not a capacitor needs to be replaced.
- There are a few checks you can do to make sure your capacitor is good to go.
- The voltage test is a quick and simple method that you’ve likely heard about before.
- A capacitor’s proper operation can be verified by applying a charge and observing the resulting voltage at its terminals.
- However, if you don’t get this reading or the voltage isn’t as high as usual after charging, you should check your cap’s compatibility with your device before continuing.
- If a polarized capacitor is involved, make sure the leads are correctly connected.
- The initial reading should be close to 9 volts (or the input voltage).
- If the voltage drops suddenly and suddenly reaches 0V, there is likely a problem with the capacitor.
- For your cap to act in this way, it’s either been damaged before or broken.
- If you suspect this is the case with your electronics, you should swap out the offending part immediately.
- It is also possible to calculate the ideal capacitor by measuring the time it takes for the capacitor to discharge to around 36.8% of the applied voltage’s peak value.
