optical indicator

optical indicator

[′äp·tə·kəl ′in·də‚kād·ər]
(engineering)
An instrument which makes a plot of pressure in the cylinder of an engine as a function of piston (or volume) displacement, making use of magnification by optical systems and photographic recording; for example, the small motion of a pressure diaphragm may be transmitted to a mirror to deflect a beam of light.
References in periodicals archive ?
Other recommended improvements include $100 for optical indicators to show people in the board room when the cameras are on and off, and a $100 audio control on the board dais that can turn the sound on and off before and after each meeting.
Four optical indicators measure flow, quantity, milking time and milk quality at each teat.
The Shelter Roof's safety features include photo switch for automatic speed reduction, optical indicators and sensors which stop the vehicle automatically at the touch of the aircraft.
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