Measurement of inductances can be made from subsonic to ultra high frequencies by a variety of means. Meaningful measurements can be made over the range of nano- henries to kilohenries, but not at the same frequency. Circuits used to characterize inductances were introduced in Section 5.2, and audio frequency inductance measuring bridges were described in Section 5.5.2. Audio frequency bridges are the most accurate means of measuring inductance at audio frequencies. In this section, we will describe two other means of measuring inductance—the ac voltmeter method, and the Q-meter