HIGH SENSITIVITY DC AMPLIFIER FOR BIOLOGICAL MEASUREMENTS
Abstract
The amplifier consists of push-pull stages from input to output circuits and provides for measurements in the range from 10 microvolts to 100 mv with 5 sensitivity positions. It is designed for use with auxiliary measuring or recording equipment having internal amplifiers. At the maximum sensitivity of 50 microvolts the peak-to-peak drift was 100 microvolts for a 30-min period. A short-term stability with 50 microvolts for 1 min is specified. The ability to discriminate against signals appearing inphase on both input grids is accomplished by the use of cathode-coupled 12J5's. The design specifications established are a sensitivity of 10 microvolts to give full-scale output with a maximum input of 100 mv, and input impedance of 10 megohms in the range 0 to 10 kc, a frequency response flat from 0 to 10 kc, an input grid current of 10 to the power of minus 10 amp, a drift less than 200 microvolts peak-to-peak over 30 min, a rise time of 10 microsecs, an in- to out-of-phase rejection ratio of 3000, and a completely line-operated power supply. A detailed circuit description and operating instructions are included.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 15, 1953
- Accession Number
- AD0011376
Entities
People
- Albert Thalhamer
Organizations
- Cornell University