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What Size Capacitor Do I Need for a 1000 Watt Amp?

Written by Edwin Jones / Fact checked by Andrew Wright


A capacitor for car audio evens out the current flow to your 1000-watt amp for a clean and smooth output. However, not all capacitors can handle your amplifier.

What size capacitor do I need for a 1000 watt amp? For every 1000-watt RMS your amp has, you’ll need at least 1 Farad.

1000 Watt Amplifier Capacitor Size Guide


You need a capacitor/condenser in your car to store energy to run the amplifier that improve the sound quality for your radio system.

There is a simple guide to determine how big of a capacitor you need for your amp. A car audio system would need a minimum of 1 farad. But you would need to increase the capacitor rating by 1 farad for every 1000 watts RMS rating of your amp.

Thus, your 1000-watt amp will need a 1 farad capacitor as a minimum. You can use a 2 farad capacitor if you want more headroom.

But a very large capacitor for your amplifier might put additional strain on your car’s electrical system. A large capacitor is another device that will be charged by the alternator, and the larger the capacitor, the larger the charging time it needs from the alternator.

Also, remember to install the 1 farad capacitor as close to the amplifier as possible. This reduces the travel length of surges.

Factors Affecting Capacitance Values

Capacitors typically have two electrodes separated by a dielectric material. How many farad a capacitor has depends on the following:

1. Electrode area

A larger conductor area increases the capacitance. Therefore, while a compact flashlight only requires a small condenser, your car radio system will require a large one.

2. Dielectric material

Some materials are better materials for capacitors than others. Film capacitors have plastic dielectric materials and are used for small capacitors. Electrolytic capacitors have an oxide film sticking to paper sheets and are common in car amps because of their high capacitance values.

3. Dielectric thickness


A thicker dielectric increases the space between the electrodes. This reduces the capacitance.


What size capacitor do I need for a 1000 watt amp? Using the simple guide to determine the right capacitor, you’ll see you’ll need a 1 farad capacitor at least.

Just remember that the capacitor is just one component of your car’s electrical system. Its performance will still depend on how good is the car’s electrical supply. So before you jump into buying a capacitor for your 1000 watt amp, make sure your alternator can handle your new device.

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