Amplifier capacitors are electronic components that store excess power. Usually used to provide additional power boost when the audio signal reaches its peak, the amplifier capacitor will increase the dynamic headroom of the circuit. Amplifying capacitors exist in every amplifying circuit, but they are especially common in automotive audio applications.

Most capacitors contain two conductive plates and an insulator between them. Small disc capacitors usually have two metal plates with a gap between the two metal plates, and the amount of charge they hold is in microfarads or picofarads. Large one-farad capacitors usually consist of two tightly wound conductive foils with an insulator between the two foils.

Farad is a measure of electrical charge, equivalent to the ability to release one ampere of electrons per second at a voltage of 1 volt. To understand that one farad represents a small amount of electricity, one should consider that a 2,000 mAh AA rechargeable battery can provide about 7,600 farads for about 7,600 seconds with an output of 1.2 volts and 1 ampere. Although batteries are orders of magnitude powerful, amplifier capacitors can be charged and discharged quickly, making them ideal for buffering applications. In fact, some signal amplifiers only use them to eliminate power supply abnormalities, because when the power supply sends too much energy, the capacitor will absorb the extra power, and when the power supply is short-circuited, the capacitor will release the power.

The auxiliary amplifier capacitor unit usually plays a role in the car audio system. Compared with the wall power supply, the power of the car is extremely limited. Therefore, loud music can absorb enough power during peak hours, which can interfere with the operation of the car and cause the headlights to dim. When an amplifier is not needed (for example, in the quiet part of a song), the capacitor will absorb additional power from the battery, and when the peak power required by the music exceeds the power that the battery and alternator can output, the capacitor will release its energy. power.

Although car audio is the most attractive user of amplifier capacitors, every amplifier uses them from the oldest tube circuits to modern solid-state amplifier designs. These components enable the amplifier to meet the signal requirements in the real world. These signals do not require huge power supplies in terms of amplitude and physical size, but the amplitude can vary greatly. For amplifiers with power limitations, adding them to the system is an economical way to improve performance without incurring the cost of upgrading to higher-power amplifiers or power supplies.