Ion channels are transmembrane proteins which are ubiquitously expressed within neurons and integral to their function. The voltage-gated subfamily responds to membrane voltage changes on the millisecond timescale. Their essential role makes them attractive pharmaceutical targets, while their low expression levels make them difficult to study in vivo. Here we replicate the ability to record the movement of voltage sensors – mobile protein domains responsible activating voltage-gated ion channels – using two-electrode voltage clamp fluorometry.