Abstract: A measurement apparatus is provided for use with a moisture tester of the type wherein the moisture content of a sample is determined as a function of the change in capacitance of a sample-receiving test cell when a sample is present therein from the capacitance of said test cell when empty. The tester also includes a reference oscillator and a test cell oscillator in circuit with the test cell, and a variable capacitor coupled in circuit with the test cell and the oscillators for bringing respective outputs of the two oscillators into a balanced condition both with the test cell empty and with a sample present in the test cell. The variable capacitor comprises a fixed member and a movable member which is rotatable through 360 degrees relative to the fixed member.