The power amplifier energy storage capacitor is not enough to cause itself

Why do power supply capacitors make noise?

Capacitors in the power supply filter out noise and ripple from the AC mains and stabilize the DC voltage feeding sensitive audio circuitry. If the power supply capacitors are of poor quality, the resulting ripple or noise can affect the audio signal, leading to hum, buzz, or other unwanted interference.

How do power supply capacitors work?

This is all very easy to follow. The load current is controlled by the transistors, which are within a feedback loop to ensure that the output signal is an accurate (but larger) image of the input signal. A point that's generally missed is that the power supply filter capacitors form part of the audio circuit, both for single and dual supplies.

Why do capacitor coupled amplifiers have negative feedback?

You'll see many capacitor coupled amplifiers (including the one shown here that I used for testing) that derive at least part of their negative feedback signal from after the output capacitor. This helps to minimise distortion created by the capacitor.

Do amplifiers use capacitor coupling?

This doesn't mean that capacitor coupling is not used though, and there are a surprisingly large number of amplifiers that still use an output capacitor. These are primarily low-power designs, and they are used in many consumer products because they are cheaper to build than a dual supply. Figure 5.2 - Voltage & Current For Symmetrical ±8V Output

What is a capacitor used for?

Capacitors are used to smooth out voltage fluctuations and filter noise from power supplies. The capacitor acts as a temporary energy reservoir, supplying power during dips in voltage and absorbing excess energy during surges. This reduces hum and noise in the audio signal caused by power supply variations.

How much power supply capacitance does a 250 watt amplifier have?

To put this capacitance in perspective, a high-quality stereo audio power amplifier, 250 Watts per channel, might have 80,000 µF of power supply capacitance (0.08 Farads). In practical applications, graphene sheets often tend to stack together, reducing the effective surface area.