How to Discharge a Capacitor with a Screwdriver

Capacitors are something that you will find in nearly any electronic device. These little thingies can store a boatload of electrical charge and can cause a shocking hazard. You won’t want to get electrocuted while setting up a new capacitor for a device.

This is why it is so important to know how to discharge a capacitor using a screwdriver. Why a screwdriver in particular? Well, because it is the most easily available tool in any house.

And if you can use it for this task, why would you need high-tech tools anyways, right? So, if you are interested in knowing about this potential hack, be sure to stick around with us till the end of this article and learn the process yourself.

Excited to know more? Let’s dive into this article!

Why Would You Need to Discharge a Capacitor?

Capacitors are pretty hazardous objects, as they may contain electric charge much long after any device is switched off. Especially when it comes to high voltage capacitors, the necessity to discharge them after use is very high.

To avoid any shock hazard, it is important that a capacitor is serviced and discharged. Whether this capacitor has been a part of a circuit or it was just there as a spare part, if it was powered, it needs to be discharged.

DO NOT be that guy who leaves a used capacitor lying around just like that and does not care about potential accidents and dangers.

Some Safety Precautions to be Taken

As it is a rather daunting task, some safety measures should be known alongside knowing how to discharge a capacitor with a screwdriver. You know what they say, “better safe than sorry,” right?

There are a few things you need to ensure you are using or maintaining while discharging a capacitor, no matter what method you use.

Make sure you have securely insulated screwdrivers and not ones that are not properly insulated. It is very much essential that you check whether the screwdriver is safely insulated, or you might risk getting “shocked” at what happens!

Other than that, you want to have safety gloves made of rubber or some kind of non-conductive material and safety goggles for your eyes. And lastly, you might require some insulated pliers, too, so keep them within your reach if you need them.

We highly advise using protective gear and equipment. However, if the charge stored in the capacitor is as low as 10V, you won’t really need the safety gears. But we would still recommend being on the safer side, nonetheless.

How Do I Discharge a Capacitor with a Screwdriver?

Now that we’ve made sure you remain safe while doing the task, it is time that we explain the whole process elaborately, so you don’t mess it up.

Set up Multimeter

We know, we said we’d show you how you can discharge a capacitor using a screwdriver only and mentioned nothing about a multimeter. Well, we are now, so just hear us out.

The first thing you have to do is set up a multimeter to see exactly how much electric charge is still in the capacitor. This is important as it will tell us how long it will take to discharge it properly.

Set the multimeter to its highest DC-voltage setting and move on to the next step.

Connect Leads

You are going to have to connect the leads of your capacitor to the probes of the multimeter. Make sure you are wearing those safety gloves, as you risk getting electrocuted.

This is technically the first step if we’re considering that you might have a multimeter ready and set up from before (yes, some people do that).

Monitor the Multimeter Display

Hold onto the probes of the multimeter with the leads of your capacitor properly. While doing so, pay attention to the readings you see on the display of the multimeter.

Note: if the readings in the multimeter are less than 50V, only then do as we advise – using a screwdriver for discharging it. Otherwise, you should use other tools.

Get an Insulated Screwdriver

Grab your insulated screwdriver and hold it in one hand and the capacitor in your other hand. As we mentioned previously, the insulation must be properly done. No broken or damaged screwdriver handle can be allowed to be used.

So, be more vigilant about the presence of any cracks, tears, holes, or fragility in the rubber or plastic.

Place Screwdriver Across Both Leads

Take the two leads of the capacitor and place the screwdriver across them. You will notice a spark occurring, which would mean that the discharge process is in progress and will be done shortly.

Another thing you must note is that the spark might be pretty heavy if the charge is above 50V. This is something you should indeed be cautious about. Make sure you are properly wearing your safety gears and are not prone to get electrocuted or injured by the sparks.

One more thing, if the charge is too high, the screwdriver’s tip risks getting melted. So, be careful with your equipment, and don’t use a screwdriver anymore if you see the charge to be too high. We’d advise discharging the capacitor in some other way.

Check the Multimeter Again

We’re are assuming that the charge was below 50V, and you went on with discharging your capacitor using the screwdriver. You’re going to have to hold the screwdriver attached to the leads for a while and monitor the multimeter from time to time.

Take a look at the display after a little while and see whether the stored charge has gone zero or not. If you did your job right, the readings of the stored charge should come as 0V at this point.

Do Capacitors Discharge on Their Own?

Technically they do, with time. But this mainly applies to capacitors that had a low charge stored in there in the first place. You shouldn’t let a high voltage capacitor lay around after using it without discharging it manually.

However, if we are speaking theoretically, it is possible for all capacitors to discharge on their own after being disconnected from a power source. This is a gradual process and may take time, depending on the voltage passed into it.

So, if the capacitor you’re using has a very low voltage, for example, lower than 10V, you can technically leave it as it is to discharge on its own. It won’t be an issue and won’t cause any kinds of harm either.

Final Words

Was that all too hard to take in? We hope the information that we provided was comprehensive enough for you to fully know the process. At this point, you should properly know exactly how to discharge a capacitor with a screwdriver.

Be sure to follow the safety precautions that we mentioned in order to not encounter any kind of injury or hazard. Preventing potential hazards is very important. Remember guys, safety first no matter what!

We hope you had a fun time reading this article and found it informative enough. Good luck working on that device of yours!



Shawkat is a passionate home and auto mechanic who enjoys sharing his knowledge with others. He has been working on cars and homes for over 9 years and has a wealth of experience to share. From indoor tools to outdoors, crafting to automotive, you will see his passion for tools. And he is not alone here, either. He collaborates with other users to give you the best possible tool experience. As the founder of Geartoolsbuddy, Shakat is always happy to help people with their queries and doubts about power and hand tools.