Everything about your electric guitar contributes to its overall sound. The way your guitar is shaped, the type of pickups you use and the knobs on your guitar all affect the sound that comes from your guitar and out of your electric guitar amp. The knobs on your guitar, in different variations, provide volume and tone control for your guitar.
The volume knob is exactly what it sounds like. Some guitars only have a volume knob. Some volume knobs have a dial printed on the knob itself numbered 1 through 10. If you turn the volume knob in the clockwise direction the volume will increase, and if you turn the knob in the counter-clockwise direction it will decrease your guitar's volume.
The tone knobs on your guitar act as a built-in equalizer on your guitar, which control high and low frequencies produced by your guitar's pick-ups. Some guitars have only one tone knob next to the volume knob. Other guitars have as many as three or four tone knobs. The more tone knobs your guitar has, the more control you have over your guitar's tone.
The pickup switch allows you to activate a single pickup or set of pickups on your electric guitar. Your guitar's pickups produce different tones and sounds depending on the location of each pickup on the body of your guitar and the type of pickup installed.
Turning the knobs on your guitar all the way up may produce a very thin, tinny or flimsy guitar tone. The higher you set your tone knobs, the higher the frequency it will produce, and the volume knob will only amplify your tone knob settings.
Your tone knobs, volume knob and pick-up selector are wired to your guitar pickups by small, delicate wires. Being careless or forceful with the knobs will result in crackling sound when you turn the tone and volume knobs, which eventually results in broken tone and volume knobs.