AH 1100
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AH 1100 Capacitance Standard Frame AH 11A Fused-Silica Capacitance Standard The World’s Most Stable Capacitance Standards1 The AH 1100 capacitance standard frame containing from one to four AH 11A fused-silica capacitance standards provides reference capacitors of unexcelled stability. The inherent stability of this system when subjected to mechanical or thermal shock makes it the ideal transfer standard for Outstanding Features • Any capacitance value in the range from below 1 pF up to 115 pF may be ordered. • Stability of larger capacitors is better than 0.3 ppm/year. • Temperature coefficient of the capacitance with respect to changes in ambient temperature is less than 0.01 ppm/°C. capacitance. The built-in precision temperature controllers make it a simple, reliable system to use. These are the only standards currently sold that are sufficiently accurate to calibrate the AH 2500A capacitance bridge to the limits of its specifications. • The user-selected capacitance value is set at the factory to a NIST traceable accuracy of 2 ppm at 1 kHz. • The built-in precision oven in each AH 11A uses a dual temperature sensor system which provides increased reliability and confidence. • The AH 1100 frame provides monitoring of critical temperature control parameters such as the differences within the dual temperature sensors in each standard. • Each AH 11A standard can be easily removed from the AH 1100 frame. Their small size and light weight make them easy to ship for calibration. • Shipping is simple since continuous temperature control of the ovens is not needed to maintain the stability specification. • The fused-silica element is hermetically sealed in dry nitrogen. • Three-terminal BNC connections minimize connector costs and number of cables. Hysteresis resulting from temperature cycling is less than 0.05 ppm. • Hysteresis resulting from mechanical shock is less than 0.05 ppm. • AC voltage coefficient is less than 0.003 ppm/volt. • DC voltage coefficient is less than 0.0001 ppm/volt. • Power line sensitivity is less than 0.0003 ppm per 1% change in power line voltage. • Dissipation factor is less than 0.000 003 tan 8 • Three year

BRIEF HISTORY Capacitance standards using fused silica as a dielectric have been investigated at NBS (now NIST) for many years. Some particularly thorough research was done in the early 1960’s by Cutkosky and Lee1. They constructed BASIC DESIGN AH 1100 Frame The AH 1100 frame consists of a 3.5 inch (8.9 cm) high, standard width, bench-top or rack-mountable frame. This frame can hold up to four AH 11A fused-silica capacitance standards. The frame provides the electrical power to operate the precision temperature-controlled oven that is part of each AH 11 A. The frame also provides the...

Range of capacitance values that can be ordered: Any value from below I pF up to 115 pF Accuracy of initial setting: 2 + 1/C ppm at 1 kHz where "C" is the value of the 11A in pF. Stability in ppm per year: 0.3 + 1/C ppm/year Temperature coefficient relative to a change in ambient temperature: 0.01 ppm/°C Hysteresis from temperature cycling: 0.05 ppm Hysteresis from mechanical shock: 0.05 ppm AC voltage coefficient: 0.003 ppm/volt rms at 1 kHz DC voltage coefficient: 0.0001 ppm/volt Sensitivity to power line voltage changes: 0.0003 ppm per 1% change in power line voltage Dissipation factor:...