Low cost instrumentation amplifier

Amplifier can be used for many applications requiring high input impedance and common mode rejection, low drift, and gain accuracy on order of one percent. Performance of inexpensive amplifier approaches that of some commercial instrumentation amplifiers in many specifications

Development and design of three monitoring instruments for spacecraft charging

A set of instruments which provide early detection of potentially dangerous geomagnetic substorm conditions and monitor the spacecraft response are discussed. The set consists of a sensor that measures the characteristic energy of collected electrons or ions from + 100 to - 20,000 V, a logarithmic current density sensor that measures local electron flux and a transient events counter that counts the spurious pulses from electrostatic discharges that couple into the spacecraft wiring harness. Design details and performance characteristics of the three instruments are given. Size, weight, and power requirements are minimized

Wide-range nuclear magnetic resonance detector

Compact and easy to use solid state nuclear magnetic resonance detector is designed for measuring field strength to 20 teslas in cryogenically cooled magnets. Extremely low noise and high sensitivity make detector applicable to nearly all types of analytical nuclear magnetic resonance measurements and can be used in high temperature and radiation environments

Optically isolated logarithmic nanoammeter capable of floating to 5 kilovolts

A logarithmic current-measuring instrument was developed to measure plasma coupling currents at a common mode voltage of 5 kilovolts. Positive or negative currents can be measured from 10 to the -9th power to .001 ampere direct current. Optical isolation is used to control input switching and to provide data referenced to ground potential. Analog meter readouts as well as zero to five volt outputs are provided for peripheral data collection. Six independent channels are provided. Three measure positive currents, and three measure negative currents. Although designed for vacuum operation, it can be used equally well in air to measure low currents at high common mode voltages

Data acquisition from high-speed rotating shafts

Data system, when used with a rotary transformer, results in increased life, negligible noise, and capability for a large number of data channels in testing rotating equipment. It is used to multiplex many channels of analog transducer output data and convert this signal to binary digital output

Plastic preforms facilitate fabrication of welded cordwood electronic modules

Molded plastic preform facilitates the fabrication of small lots of welded cordwood circuits. The preforms retain the components during welding and electrical checkout and facilitate encapsulation of the welded module when used with a conventional potting shell

Low-cost voltage-level detector

Integrated circuit senses when the voltage level has exceeded or is below a given reference level. The circuit, consisting of a differential amplifier, an SCR, and a pair of zener diodes, is useful for overload detection and monitoring power supplies

Dual-voltage power supply has increased efficiency

Simple circuit provides two different dc output voltages from an ac source. It employs a full-wave rectifier connected to two passive branches from which the separate dc voltages are taken. The outputs have low ripple and good voltage regulation

A 20 kHz power oscillator

Circuit providing stable sine wave power up to 10 W supplies small amounts of power at frequency other than 60 Hz. Circuit has Wien bridge oscillator which uses operational amplifier to feed power amplifier stage. Power amplifier stage uses booster amplifier and two discrete transistors for power output

Why Do Employees Keep Choosing the Expensive Health Care Plan? An Investigation of the Quality and Logic of Employee Health Care Plan Selections

In 1991, The Dannon Company provided 287 of its employees with a choice of healthcare plans. The new plan was less expensive and designed to fit employees\u27 needs better. Contrary to managerial expectation, three-quarters of employees continued to choose the more expensive plan. To study why this was occurring and to determine if these choices reflected employee mistakes, a cooperative effort was begun between The Dannon Company and Cornell University. This cooperative effort allowed us to investigate this problem using actual employee medical claims. Analysis revealed employees strive not only to minimize costs, but also to avoid risk in their health care plan decisions. Overall, employees with the most significant cost difference chose the plan with the lowest total costs. This effect translated into financial savings for the employees. Employees were better off as a group with the freedom to make their own selections than they would have been if they had been forced into either of the two available health care options. Thus, this study demonstrated that choice is valuable to employees. Implications for Dannon and for future research are discussed