The Andeen-Hagerling Model 2500A measures capacitance and loss in medium and high impedance ranges, and thus allows using three-terminal rather than five-terminal connections to the unknown.

Its unmatched precision is the result of a uniquely designed ratio transformer: the culmination of 15 years of Andeen-Hagerling bridge design and manufacture. Equally important is the unique temperature-controlled, fused silica capacitance standard which allows extremely high measurement stability and immunity to mechanical shock.

These elements combine to form a true bridge operating at 1 kHz to give capacitance results which are independent of the exact test frequency.