Abstract: A test set for measuring magnetic properties of magnetic amplifier cores wherein a repetitive constant current sinusoidal drive signal for producing a magnetic field in the core is repeated at a low duty cycle rate of not more than one full sine wave in one hundred sine waves. The test set includes a test fixture wherein portions of the primary and secondary windings are connected in a cover and table and terminate in mating contacts rigidly extending therefrom, such that when the cover is moved from the table, the windings are separated at their mating contacts so that a test core can be inserted within the windings.