A capacitor is an essential component of any and all electronic devices. Capacitors are short term charge-stores, a bit like an electrical spring. They are used widely in electronic circuits. It consists of two metal plates separated by a layer of insulating material called a dielectric. There are two types of capacitor, electrolytic and non-electrolytic. We won’t worry at the moment what these terms mean, other than to say:
- Electrolytic capacitors hold much more charge;
- Electrolytic capacitors have to be connected with the correct polarity, otherwise they can explode.
If we pump electrons onto the negative plate, electrons are repelled from the negative plate. Since positives do not move, a positive charge is induced. The higher the potential difference, the more charge is crowded onto the negative plate and the more electrons repelled from the positive plate. Therefore charge is stored. The plates have a certain capacitance.
Capacitance is defined as the charge required to cause unit potential difference in a conductor.
A very good example would be a capacitor used on audio electrical devices such as in a car sound system setup. The capacitor is the one responsible for storing sufficient energy into the amplifier so that it won’t have to steal for electrical currents from the car battery to be able to output energy-consuming low frequency bass sounds. Since capacitors can store electrical currents for an indefinite period of time even if it is not hooked up to any power source, then a capacitor can be extremely dangerous when not discharged correctly. So if for some reason you will need to have the capacitor uninstalled or removed, it has to be discharged properly and completely. This is so accidental electrocution which could be potentially fatal to you can be avoided. Also, damaging power surges that can burn up or cause short circuits on the components of the electrical device can be prevented. Use these tips for discharging a capacitor. Here’s how to understand some methods to discharge a capacitor.
Observe the important safety measures prior to discharging the capacitor. As was earlier said, capacitors hold electric currents even when not connected to any power source. This being said, capacitors, especially those with high capacitances, can hold substantial loads of electric currents for days. These could go off and spark causing electrocution and short circuits when discharging is not properly done. This is why it is important to arm yourself with the necessary safety gears especially if you’ll be discharging a high-voltage capacitor. Never attempt to discharge a capacitor without protective goggles shielding your eyes. There have been cases where fragments of the tools used to discharge the capacitor flew off in sparks. Also, it would be advisable to wear a pair of highly insulated utility gloves for added safety as this will help minimize the electrical currents that will course through your body in case you get electrocuted. And of course, using the right tools and materials for discharging the capacitor is very crucial. While you can always improvise on these, you increase the odds of getting into accidents.
Discharging a capacitor simply means giving the stored electrical currents a path out of the apparatus. To discharge a small capacitor, touching the two lead terminals with the tip of screwdrivers with insulated handles should do the trick. However, this is not recommended, except of course if you’re a mechanic or electrician with years of experience in the said matter. Handling high-voltage capacitors, on the other hand, is a different story altogether. You have to attach the supplied resistor or test light onto the capacitor’s terminals to safely dissipate the stored electrical currents.
To make sure that you completely discharge the capacitor after following the aforementioned steps, you can touch the terminals with the tips of the screwdriver once more. Alternatively, have a light bulb handy for the purpose. Simply touch its threaded base onto one of the capacitor’s terminals. If it still contains electrical charges, it will light the bulb up. 
