1.a room is to be maintained at 73 °f. the outside temperature is 92 °f. there are 11 people in the room, each generating 320 btu/hr of heat. there are 1800 watts of lighting in the room, of which 20 % goes to heat. the room has one outside wall (with no windows), which has r-8 insulation and an area of 240 ft2. the room is being cooled by air conditioners with an eer rating of 9. assume the eer rating stays constant no matter what the outdoor temperature. a.what is the heat gain in the room due to people? (include units with answer)hint #1: same units as heat generated, given in problem. b.what is the heat gain in the room due to the lighting? (include units with answer)c. what is the heat gain in the room due to heat conduction through the outside wall? (include units with answer)hint #1: r-8 means the thermal resistance is 8 (ft2-hr-°f)/btud. how much electrical power is required to run the air conditioner? (include units with answer)hint #1: eer has units of (btu/hr)/watt. use these mixed units to your advantage! e. if the air conditioner were running at the maximum possible efficiency, how much electrical power is required to run the air conditioner? (include units with answer)

Ithink i did this class in 7th grade doe i don’t remember

Infrared sensor is most used sensor in wireless technology where remote controlling functions and detection of surrounding objects/ obstacles are involved. this post will discuss about what is infrared sensor, its working principle, how it works, types, applications, advantages and disadvantages. what is infrared sensor

ir sensor is a simple electronic device which emits and detects ir radiation in order to find out certain objects/obstacles in its range. some of its features are heat and motion sensing.

ir sensors use infrared radiation of wavelength between 0.75 to 1000µm which falls between visible and microwave regions of electromagnetic spectrum. ir region is not visible to human eyes. infrared spectrum is categorized into three regions based on its wavelength i.e. near infrared, mid infrared, far infrared.

wavelength regions of infrared spectrum

near ir – 0.75µm to 3 µm
mid ir – 3 µm to 6 µm
far ir – > 6 µm
1 introduction to infrared sensor

fig. 1 – introduction to infrared sensor

working principle of infrared sensor

infrared sensors works on three fundamental physics laws:

planck’s radiation law: any object whose temperature is not equal to absolute zero (0 kelvin) emits radiation.
stephan boltzmann law: the total energy emitted at all wavelengths by a black body is related to the absolute temperature.
wein’s displacement law: objects of different temperature emit spectra that peak at different wavelengths that is inversely proportional to temperature.
key elements of infrared detection system

the key elements of infrared detection system are:

ir transmitter

ir transmitter acts as source for ir radiation. according to plank’s radiation law, every object is a source of ir radiation at temp t above 0 kelvin. in most cases black body radiators, tungsten lamps, silicon carbide, infrared lasers, leds of infrared wavelength are used as sources.

transmission medium

as the name suggests, transmission medium provides passage for the radiation to reach from ir transmitter to ir receiver. vacuum, atmosphere and optical fibers are used as medium.

ir receiver

generally ir receivers are photo diode and photo transistors. they are capable of detecting infrared radiation. hence ir receiver is also called as ir detector. variety of receivers are available based on wavelength, voltage and package.

ir transmitter and receivers are selected with matching parameters. some of deciding specifications of receivers are photosensitivity or responsivity, noise equivalent power and detectivity.