The Beckman D-2 analyzer is an example of a paramagentic oxygen analyzer. The prototype was developed in the 1940s by Linus Pauling and enhanced by Arnold Beckman. Production of the Beckman D-2 Analyzer began in the 1950s.
Image from Illinois Central College Archives, 1999
The Mira oxygen analyzer is an example of a Wheatstone bridge or thermoconductivity analyzer.
Image from Tony Ruppert
The Ventronics analyzer is an example of a galvanic fuel cell or electrochemical oxygen analyzer.
Image from Glenn Tammen
The Hudson Oxygen Analyzer is an example of a galvanic fuel cell.
Image from Rusty Taylor
The H-P Ear Oximeter was released in 1976. The device weighed 37 pounds, and was 7.5 in x 17 in x 17 in. The probe was positioned on the pinna of the ear. The ear was covered by a shield to block out ambient light.