Pulse relaxation amplifier ¿ A low-level D-C magnetic amplifier

DEMAND for stable amplifiers to work at extremely low signal levels has attracted the attention of all who design and build amplifiers. The pulse relaxation amplifier (pra) is an outgrowth of this demand. It is essentially a magnetic amplifier requiring no rectifiers and operating from a pulse power supply. Preliminary tests indicate a zero drift level of less than 10¿16 watt over a temperature range from ¿70 to 140 degrees centigrade. This is compared to 10¿8 watt attainable with conventional amplistats (self-saturating magnetic amplifiers). They are temperature-limited primarily because of their rectifiers. The two greatest sources of drift in amplistats, variation in rectifier and magnetic-core characteristics, have been eliminated in the pra.