HIGH-FREQUENCY VOLTAGE STANDARDE&MP 44.045 Electricity - High-frequency Voltage March 11, 1949 Figure 1. a NEW PRIMARY RADIO-FREQUENCY VOLTAGE STANDARD DEVELOPED BY THE National Bureau of Standards makes available high-precision voltages without any frequency corrections. Effective coverage is provided in the range from 10 millivolts to 10 volts at frequencies up to 50 Mc. The standard consists of a voltage-measuring thermistor bridge, a special thermistor mount, instantaneous and simultaneous r-f/d-c switching arrangement, a d-c voltage source stability of the order of 1 part in 107 per minute, and d-c measuring circuitry with a sensitivity of 1 part in 107 (measurement accuracy of 1 part in 105 to 1%). The equipment is shown in an experimental arrangement, with the thermistor
mount and coaxial switch at left.
Original Caption by Science Service |
