How to Check Capacitor Polarity with a Multimeter

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There’s no doubt that capacitors play a crucial role in the family of passive electronic components, not to mention their uses can be found everywhere! 

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Just take a look at your digital camera’s flash. Did you know capacitors make that happen? What about the ability to change the channel on your television? Capacitors made that too! These devices are the small batteries that “can,” and you will need to know everything there is to know about them before you begin working on your first electronics project.

One of the key things you need to learn about them has to do with capacitor polarity. But before we get into that, let’s have a quick peek at what a capacitor is.

What is a Capacitor?

To make it short, a capacitor keeps an electrical charge like a battery. It’s also typically called caps, as you will find these things in applications that need voltage suppression, energy storage, and even signal to filter. 

One of the common capacitors today is electrolytic capacitors. These capacitors are polarized that you can find on a circuit board. It can also hold a huge amount of electric charge inside its small footprint. It’s worth mentioning as well that they are the only type of capacitor that’s polarized! 

That means they only function when they are wired in a specific orientation. In one such electrolytic capacitor, you will find a positive pin (anode) and a negative pin (cathode). The anode should always be linked to a higher voltage.

Wiring it up the other way around with the cathode getting a greater voltage will result in an exploding capacitor. 

Despite holding a huge amount of an electric charge, these capacitors are also popular for leaking current faster than ceramic capacitors. That being said, they are not the ideal capacitor of choice, especially if you like to store energy. 

What is the Symbol of a Polarized Capacitor?

Now that we are on the topic of capacitor polarity, it’s good to learn the symbol of a polarized capacitor as well. Determining a capacitor on your initial schematic is relatively simple. That’s because they come in only two types: being standard and, of course, polarized.

These two types are very much different, especially the polarized capacitor, as it has an arched line on the lower part of it, together with a positive terminal on top. That positive terminal is essential and specifies how the polarized capacitor should be wired.

Take note that the positive side often gets connected to the power, while the arc side connects to the ground. 

How Does an Electrolytic Capacitor Work?

Electrolytic capacitors are typically utilized when huge capacitance values are needed. Instead of utilizing a small metallic firm layer for the electrode, a semi-liquid electrolyte solution in the form of paste or jelly is utilized, serving as the second electrode.

The dielectric is a thin layer of oxide that is electro-chemically grown in production, with the thickness of the film being less than ten micrometres. That insulating layer is so extremely thin that it’s possible to create capacitors with a huge volume of capacitance for a tiny physical size. That’s because the plate’s distance is extremely small.

Most electrolytic capacitor types are polarized. That’s the DC voltage used to the capacitor terminals should be of the accurate polarity. For instance, the negative to the negative terminal and positive to the positive terminal as wrong polarization will break down the insulating oxide layer and cause permanent damage. 

Take note that every polarized capacitor should have its polarity designated with a negative sign, telling the negative terminal and that polarity should always be followed. 

It’s worth mentioning as well that electrolytic capacitors are often utilized in DC power supply circuits. That’s possible because of their big capacitance, and trivial size for coupling and decoupling uses or to help decrease the ripple voltage. 

One of the key benefits of electrolytic capacitors is their low voltage rating. Because of the electrolytic capacitor’s polarization, it should not be used on AC supplies. 

How Do You Check the Polarity of a Capacitor?

 One simple and practical way to check the polarity of a capacitor is with the use of a digital multimeter. Engineers and electricians use this tool to compute capacitance for single-phase motors, machines, and equipment small in size for industrial applications.

Electrolytic capacitors are ideal for high capacitance uses like a motherboard for computers and power supply circuits. A multimeter works by computing voltage and current using two values to measure capacitance. Follow the steps below, so you are guided on how to check capacitor polarity with a multimeter.

  1. Get your digital multimeter and see it to capacitance mode. That setting is often specified by a capacitance symbol (like this –|(– one here).  
  1. Now, connect your capacitor to the circuit and give it some time to charge. Remove it from the circuit after following all the safety precautions specified.
  1. Attach the leads of your capacitor to the digital multimeter terminals. You can utilize a relative mode to check the test lead’s capacitance relative to one another. That can be convenient for low capacitance values, which might be more complicated to locate.
  1. You can use other capacitance ranges until you get the reading that is accurate according to the electric circuit’s configuration. 

Final Thoughts

And there you go, everything you need to know about capacity polarity and electrolytic capacitors to get all charged up for your next electronics project. As you can tell, capacitors are, no doubt, a remarkable small bunch capable of storing an electric charge for a wide array of uses. The best part here is they can function as a secondary power source for those delicate integrated circuits (IC). 

There’s one thing you need to keep in mind, though. Always be extra mindful and cautious of the maximum voltage possible every time you are working with these capacitors. Otherwise, you will end up with some exploding capacitors. We wish you the best of luck and hope you enjoyed reading this guide!

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