Shockley-Ramo theorem

The Shockley–Ramo theorem allows one to easily calculate the instantaneous electric current induced by a charge moving in the vicinity of an electrode. It is based on the concept that current induced in the electrode is due to the instantaneous change of electrostatic flux lines which end on the electrode, not the amount of charge received by the electrode per second. The theorem appeared in William Shockley's 1938 paper "Currents to Conductors Induced by a Moving Point Charge" and a year later in Simon Ramo's 1939 paper entitled "Currents Induced by Electron Motion".

The Shockley–Ramo theorem states that the instantaneous current i induced on a given electrode due to the motion of a charge is given by:

where

This theorem has found application in a wide variety of applications and fields, including semiconductor radiation detection and calculations of charge movement in proteins.

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