Fast-response magnetic amplifiers

AMPLIFIERS for use in automatic control systems should feature high gain, high-power output, and fast response along with light weight and reliable operation. In electrical systems magnetic amplifiers are gaining favor because of their rugged construction, but until recently the response time of magnetic amplifiers has been relatively unsatisfactory for small servo systems. Amplifiers are often characterized by a time constant, but for carrier devices the number of cycles for 100 per cent response is sometimes a preferable characterization. In an elementary carrier type amplifier 100 per cent response can be obtained in 1/2 to 3/2 cycles depending on the time within the cycle at which the input change is applied. Gas tubes, for instance, achieve this result. This general behavior is often spoken of as single-cycle or half-cycle response. In this paper fast-response magnetic amplifiers are considered to be those which respond fully to an input change within 2 cycles of the carrier frequency.