A Voltage Clamp is a technique used in cellular biochemistry to measure Ionic currents in relation to a cell. It is a process where a voltage potential moving across a cell membrane is controlled and the current measured. The observation of the movement can be used to measure Ionic movements across said membrane.
The calculation involved in the measurement is the sum of the Ionic current and the capacitance current, with the capacitance current defined as i = C x (dv/dt).
This method was developed in in 1949 by Marmont and Cole and then Hodgkin, Huxley and Katz.