The emf induced by the string vibrating is modelled by the AC source. The 2nd order LC filter created by the 2.5H inductor, 8k resistor, and the 150pf capacitor models the characteristics of guitar pickup. The 8k models the resistance of the winding. The inductor models the coil inductance of the pickup and the 150pF cap models the interwinding capacitance.
The first 250k pot is the volume control on the guitar. The second 250k pot in series with the 20nF cap is the tone control.
The final 200pF cap models the cable inductance from the guitar to amp/pedal/etc.
Notice how changing the cable capacitance as well tone control capacitor (20nF) shifts the resonant peak of the magnitude response. A resonant peak at higher frequencies creates a brighter guitar tone, and a warmer tone as the peak moves lower. A longer cable creates a larger capacitance - meaning a warmer tone!!
If you're a guitar player, hopefully you find this interesting.
-All The Best
