How to Build a Capacitor

Capacitors range from a simple, low-voltage setup to complex high-voltage machinery. If you just want to try your hand at making a simple capactior, our how-to guide will show you how!

Steps

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Use warm water to dissolve the salt.
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Place a metal object (such as a knife, a nail, etc) in the saltwater. The foil is one terminal, and the water/metal object combination is the other. Do not allow the water or the metal object to touch the foil or spill over the side. This will short the capacitor and make it impossible to charge.
- Later you can use a voltmeter to verify if the capacitor can hold a charge.
After a few seconds disconnect the battery and connect the voltmeter to the terminals of the capacitor. Any reading (mV-V) will indicate a charge.

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Question
What is the advantage of a salt water capacitor over a water capacitor?
Community Answer
Salt water is more conductive than plain water, so it will hold a charge better.
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Question
Does the capacitor have any specific polarity?
Community Answer
Some do. Electrolytic capacitors have the polarity marked. Hooked up backward, they pop and let the magic smoke out. Other types are not polarity sensitive.
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Question
Do I need to wrap the bottom of the capacitor?
Community Answer
Not necessarily. The capacitive effect occurs from the separation of the two plates (conductors). Not wrapping the bottom reduces the size of the plates (conductors), resulting in less capacitance, or a less capacitive effect, so you just have a smaller capacitor vs. the overall physical size of the unit that could have been utilized to maximize its energy potential.
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Tips

You can charge it up with a battery, or with static electricity. You cannot charge a capacitor with an alternating current, only with a direct current.
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Warnings

Capacitors are very dangerous. Do not touch one after it has been charged by a power source, because it will shock you.
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