How are resting potentials measured?

The preferred technique for measuring resting potentials is the use of a voltmeter. In this method, a special voltmeter is electrically connected to the interior of the cell using a glass microelectrode. An electrolyte solution that is filled into the microelectrode facilitates electrical continuity between the interior of the cell and the wire connected to the voltmeter. The electrode converts ionic current to electrical current, which is sent to the voltmeter. Because the magnitude of membrane potential is very small, the voltmeter must also amplify the signal for accurate measurement.