Nonlinear Circuit Elements Research Articles

An accurate electronic tracer for dynamic characteristics of magnetic materials

THIS equipment makes possible the accurate determination of dynamic magnetic characteristics needed for advanced magnetic amplifier design. The hysteresis loop and the time functions of H, B, and dB/dt can be either measured point by point or continuously recorded on an x-y recorder by means of an automatic electronic a-c compensator which transforms the a-c signal for any given time instant into an equivalent direct voltage. An over-all accuracy of 1 per cent is possible for operating frequencies between 50 and 1,000 cycles per second (cps). The instrument is valuable not only for studying the dynamic characteristics of magnetic materials but also for the evaluation of other nonlinear circuit elements like rectifiers, transistors, and ferroelectric capacitors.

New developments in differential-type hydraulic transmissions and controls

The differential-type hydraulic transmission has been used as a constant speed drive for aircraft a-c generators for approximately 8 years. The experience gained in this time on both the B36 and P5M airplanes has been a major factor in establishing future aircraft electrical system and component requirements. However, the final decision to establish closer electrical system tolerances for voltage and frequency, real and reactive load balance, and necessary fault protection should be determined on the basis of component and system reliability, simplicity, and performance. The following discussion considers these important characteristics for the components controlling system frequency, real-load division between paralleled a-c generators, and automatic paralleling of a-c generators. The improvements in new system performance were gained by utilizing components with faster response times, and also by the introduction of nonlinear circuit elements. Design and performance details are cited to substantiate steady-state frequency control to within 0.25 per cent of 400 cycles per second, real-load division to within 2 kw, and automatic paralleling of generators to maintain current transients within generator full-load ratings.

High saturation magnetic alloy with a rectangular hysteresis loop

A study has been made of magnetic alloys which have a nearly rectangular hysteresis loop. This characteristic is desirable for materials used in saturable reactors, magnetic amplifiers, pulse transformers, and other nonlinear circuit elements.

OSCILLOGRAPH STUDY OF DIELECTRIC PROPERTIES OF BARIUM TITANATE

AbstractA disk of barium titanate was fired to 1350°C. for six hours in an electric furnace. Silvered electrodes were then fired on the disk at 650°C. A cathode‐ray oscillograph measurement was made of the dielectric properties in order to analyze the whole charging and discharging cycle. The material showed saturation of the dielectric flux density or charge with increase of field strength or voltage and is therefore a new type of ferroelectric material. The dielectric properties of such a nonlinear circuit element was studied over a temperature range from –175° to +140°C. at field strengths of 59, 134,234, 580, and 4300 volts per cm. Peaks in the dielectric constant were observed near –70°, +10°, and 120°C. As the field strength was increased, the two lower peaks increased in magnitude and all peaks shifted slightly to lower temperature.