What is Detector: Definition and 276 Discussions

In the broadest definition, a sensor is a device, module, machine, or subsystem whose purpose is to detect events or changes in its environment and send the information to other electronics, frequently a computer processor. A sensor is always used with other electronics.
Sensors are used in everyday objects such as touch-sensitive elevator buttons (tactile sensor) and lamps which dim or brighten by touching the base, besides innumerable applications of which most people are never aware. With advances in micromachinery and easy-to-use microcontroller platforms, the uses of sensors have expanded beyond the traditional fields of temperature, pressure or flow measurement, for example into MARG sensors. Moreover, analog sensors such as potentiometers and force-sensing resistors are still widely used. Applications include manufacturing and machinery, airplanes and aerospace, cars, medicine, robotics and many other aspects of our day-to-day life. There are a wide range of other sensors, measuring chemical & physical properties of materials. A few examples include optical sensors for Refractive index measurement, vibrational sensors for fluid viscosity measurement and electro-chemical sensor for monitoring pH of fluids.
A sensor's sensitivity indicates how much the sensor's output changes when the input quantity being measured changes. For instance, if the mercury in a thermometer moves 1 cm when the temperature changes by 1 °C, the sensitivity is 1 cm/°C (it is basically the slope dy/dx assuming a linear characteristic). Some sensors can also affect what they measure; for instance, a room temperature thermometer inserted into a hot cup of liquid cools the liquid while the liquid heats the thermometer. Sensors are usually designed to have a small effect on what is measured; making the sensor smaller often improves this and may introduce other advantages.Technological progress allows more and more sensors to be manufactured on a microscopic scale as microsensors using MEMS technology. In most cases, a microsensor reaches a significantly faster measurement time and higher sensitivity compared with macroscopic approaches. Due to the increasing demand for rapid, affordable and reliable information in today's world, disposable sensors—low-cost and easy‐to‐use devices for short‐term monitoring or single‐shot measurements—have recently gained growing importance. Using this class of sensors, critical analytical information can be obtained by anyone, anywhere and at any time, without the need for recalibration and worrying about contamination.

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  1. B

    Where Can I Find Top-Notch IR Sensor Solutions for My System?

    Hello, Every member: We need to IR sensor solution for our system. Please, connect to me If you know any company of product or maker about the IR sensor. Required specifications are as follows: (ps: choose one of the following five.) 1. Thermopile array #1: a. Pixel pitch: 0.6 mm b. Array...
  2. anorlunda

    Is the Fermi Gamma Ray Detector Capable of Detecting Individual Photons?

    Today's APOD shows an animated visualization of a gamma ray flare detected by The Fermi Space Telescope. The video says, "each circle represents one gamma ray" That language suggests single photon detection. Is that correct?
  3. R

    Role of Bias Voltage in Semiconductor Light detector

    Good day!, today, i visited an Institute about Semiconductor devices, One characterization device (Reflectance Spectrometer) which used to determine the reflectance of the semiconductor materials. This device used Semiconductor detector to detect the reflected light from the sample, but I'm...
  4. N

    Eigenvalue based blob detector

    Hey all, I just read up on the principle of centrality, where "Think of a "network" as an NxN matrix, which has information about how N people (or N pages or N countries..) are connected to each other. Adjacency Matrix is an NxN matrix, let's say it looks something like this. People who...
  5. BUI TUAN KHAI

    Optical Properties of scintillator detector

    Dear all, I would like to study more about the optical properties of scintillator detector in nuclear physics experiment. Is there any good reference for this? If the reference is discussed deeply in solid-state-physics, that is really nice. Actually, I am attending a "optical properties of...
  6. U

    What is the expected rate of reactions in the detector?

    Homework Statement A reactor fires out ##10^{21}## neutrinos per second. A detector containing ##10m^3## of liquid which contains 30 carbon atoms every 60 hydrogen atoms. The detector-reactor distance is ##1000##. The cross section for the reaction is ##\sigma = 10^{-46} m^2##, and the density...
  7. E

    Understanding How Camera Detectors Work - CCD vs. CMOS Sensors

    How does a camera detector work? For example inside a room.. how does the equipment tells whether there is a hidden camera with ccd or cmos sensors recording video of you? Does it scan for the ccd/cmos presence or it absorbing the photons or does the detector send laser in every millimeter of...
  8. U

    Single photon double slit, reset detector after each impact

    What is the experimental outcome of a single photon or electron double slit experiment under the constraint that after each detection the detector material is reset to the original state ie, in the limit it is substituted by another detector sheet, or photographic plate. Of course that the...
  9. L

    Function of bias resistor in semiconductor detector

    Hi, I am working on CdZnTe detector. Can anyone please explain the function of bias resistor in radiation detector setup & how to select an appropriate bias resistor?
  10. Nick666

    Length contraction, train along a line, and a detector

    I was reading a closed thread here about the length contraction being real or not. The best I could understand my self is that space is the one that contracts, the final post by an experienced forum member saying something like its the space-time that changes, it rotates. But I still have to...
  11. 1

    Calculating range of muons in a detector?

    Homework Statement If one can approximate NOvA detectors being built out of hundreds of "sandwiches" or PVC plastic of 1cm thickness and a "plane" of oil of 5.6 cm, what is the range of muon of energy 200MeV, 500MeV, 1GeV, and 1.8GeV in the detector? Homework Equations \frac{dE}{dρ*x} =...
  12. Naeem Anwar

    Relative Angular Momentum in 2 Body Decay at Detector Level

    How the relative angular momentum of two particles can be detect by detector in two particle decay (center of mass frame)? I am curious about the signatures/differentiation between different relative momenta, means how one can decide that it is L=0, L=1,2,3,...? Of course the distribution would...
  13. Naeem Anwar

    Exploring New Physics with Mu2e: The Search for Leptoquarks

    Just read a report on Muon to Electron conversion experiment ground breaking at Fermilab today. What kind of new physics one can probe from this flavor changing among leptons? http://www.symmetrymagazine.org/article/april-2015/mu2e-breaks-ground-on-experiment
  14. nurul anuar

    High purity germanium detector

    hi there! I am nurul ain,new member here. I have a question regarding gamma ray detector, the high purity germanium detector or aka HPGe. What is meant by the detection efficiency at specific gamma-ray energy (εγ)? and whether the emission probability of the corresponding gamma-ray energy and...
  15. L

    Can a single atom be excited by a single photon in a vacuum tube?

    I need electron transition detector that can respond to a dozen of photons.. so the atoms detector needs to be about just a dozen too.. I need something that can read it in an output.. what instruments is this? Geiger counter detects radiation by the click of the device.. I need something...
  16. M

    Engineering Detector of even numbers in logic circuit

    Homework Statement I need to make a circuit that detects even numbers. Need to find the equation for F when input A and B are both even. Input A: Word of 5 -bit signed representation in complement 2. Input B: Word of 3 -bit signed representation in complement 2. Homework Equations for B...
  17. ChrisVer

    Calculating WIMP Detection Rate in a Germanium Detector

    Homework Statement I am trying to understand how to obtain the estimated detection rate of a WIMP of mass 100~GeV into a Germanium detector of 1kg and detection efficiency of P_{eff}=70 \% . Homework Equations If you have at hand that the cross section is given \sigma = \mu_R G_F^2 (I...
  18. Greg Bernhardt

    Replacing smoke detector alarm battery help

    I know I've done this before but for some reason I am stuck. I have a smoke alarm where the battery compartment is being blocked by the permanent power. I can't disconnect or a monitoring alarm will trip (i think?). There is a great deal of tension here and any more force I feel will break the...
  19. Greg Bernhardt

    Optical DIY Exoplanet Detector with a DSLR

    Great project to do! DIY Exoplanet Detector with a DSLR
  20. G

    Energy Resolution of a solid state X-Ray detector

    Homework Statement Hi all, I have been given the task of quantifying the energy resolution of a p-i-n semi-conductor x-ray detector and present it as a value in electron volts Homework Equations %Resolution=E FWHM / Ei Where E FWHM is the full width half maximum of a peak and Ei is the...
  21. J

    High voltage not reaching Detector

    Hi, I'm working on fixing a preamplifier connected to a semiconductor detector. The high voltage bias supply is working ok, and the preamplifier preamplifies. I've confirmed this with a digital oscilloscope and a square wave generator under many different regimes. The preamplifier components are...
  22. J

    PMF of X for Airport Metal Detector Activations

    Homework Statement Of the people passing through an airport metal detector, 0.5% activate it; Let X denote the number among a randomly selected group of 500 who activate it. 1) What is the PMF of X i) Using th CLT (approximate PMF) ii) Using the exact distribution of X 2) P(X = 5)...
  23. ChrisVer

    Muon Interaction at ATLAS Hadron Calorimeter: Investigating Energy Dependence

    Can actually muons interact and give a signal while they go through the Hadron Calorimeter of the ATLAS? I think in general this isn't impossible, but it should depend on the muon energy... I would like to see that energy dependence, even quantitatively.
  24. M

    The detector itself contaminating double slit? How do we know?

    Just a simple question. How do we know the detector isn't messing up the double slit experiment when a single photon is shot out. When there is no detector we know the interference pattern is formed even with a single photon. If we add detector to see where the photon actually went through a...
  25. O

    Product Detector: Learn When to Use & Benefits

    Hello I am trying to learn something and really hope to get some help.. i know the use of envelope detector.. but when to use product detector? i know product detector will be more expensive than envelope detector.. please help
  26. R

    What is Nc in the R Ratio formula? re CDF detector measurements

    Ive attached the R ratio formula to this post, please could someone who is familiar with it tell me what Nc is? Does it relate at all to centre of mass energy? Thanks in advance for any help. source...
  27. B

    Photoelectric Detector and Energy Measurements

    Homework Statement Which of the following best summarizes how a photoelectric detector provides an energy measurement: Answer choices: A) As light of multiple colors falls on the detector, the detector measures the energy of just one frequency of light by having a hole of only one...
  28. BeBattey

    Undergrad Research - Parabolic Cherenkov Detector

    So I'm a senior at a lesser known university, I 'believe' I did very well on my PGRE though I don't have my scores yet, and I've maintained a 3.7 average in my physics courses. The only thing holding me back from admission into a fantastic grad program is my complete lack of research experience...
  29. O

    Product Detector vs Envelope Detector

    What will happen to product detector and envelope detector when modulation depth is increasing?
  30. F

    Double slit experiment with electrons - detector at one slit

    Hello, I'm new here, but I've been researching this subject for several months now. I'm especially interested in the double-slit experiment performed with one electron at a time, particularly with the detection apparatus turned ON. I've found this statement, or something very much like...
  31. B

    What should I be looking for when reading Op-Amps?

    So my PI suddenly decided she wants me to learn electronics. And so she started me off building a balanced detector. So here I am with this circuit I know nothing about, knowing nothing about electronics... Anyways, quick question on reading Op-Amps. In my circuit diagram, there are two...
  32. O

    Half wave vs peak detector circuit

    hello I would like to know what is the different between half wave rectifier circuit and peak detector circuit.. as what i know from half wave.. it only take the positive wave only.. then what about peak detector ??
  33. K

    Why Are Detectors for Molecular Vibration Frequencies Less Common?

    We have common detectors for radio, microwaves, visible, ultraviolet, xray and gammy rays.. but how about the infrared frequencies from molecular vibrations. The frequencies of molecular vibrations range from less than 10^12 to approximately 10^14 Hz. These frequencies correspond to radiation...
  34. C

    Phase detector for PLL with low SNR

    I'm making a system with PLL. Here's more or less a principal scheme. What happens here is that the signal in this compensating system becomes really low and phase detector might not work properly. What I want to ask, what type or how to make a phase detector which can detect phase correctly...
  35. C

    CERN - new radiation detector technology

    Where would you use our new radiation detector? We are a student team from the Vienna University of Economics and Business. Currently we are working on project with the research center CERN and try to find different application possibilities for an innovative technology by interviewing...
  36. M

    Dimensions of radiation detector and range of secondary particles

    Hi All, Just reading up on methods of neutron detection and something struck me. Generally these types of detectors are manufactured small enough so the the ranges of the charged particles (usually tritium and alpha) are smaller than the dimensions (so around 100microns or so). This means...
  37. PhizKid

    How to calculate detector voltage from resistances?

    Homework Statement The resistances: Ra = 10 ohm Rb = 10 ohm Rc = 10 ohm Rd = 8 ohm Battery = 10 volts Voltage across detector = ? Homework Equations V = IR (series) R = R1 + R2 + ... (parallel) 1 / R = (1/R1) + (1/R2) + ... The Attempt at a Solution So to get the...
  38. B

    Visualization of detector data / other ideas for viz application

    Greetings friendly physics folks, I could use some advice and/or general suggestions regarding a data visualization project I'm looking to get started on. If this looks like too much reading, please skip to the TL;DR below. The basic project components are: (1) A GUI of some kind...
  39. FOIWATER

    A positive peak detector circuit

    I am building a positive peak detector circuit using AD829 opamps. I have attached my current circuit I built in multisim. I used a "superdiode" configuration on the charging circuit so that I simultaneously get the charging across the capacitor, no discharging during the falling edge, and...
  40. marellasunny

    Radar as range detector between cars-static sender vs dynamic sender

    Say I have a radar transmitter on a car,used to detect its distance from a car in front of it by measuring the doppler shift on the reflected wave. i.e Car 1 is the source, its wave gets reflected by Car 2 in front of it. My book splits the problem of calculating the Doppler shift by computing...
  41. O

    Calculating gain of a phase detector

    I have a linear model of a phase detector (phase lock loop) represented by the block diagram below. It is designed to maintain zero difference in phase between the input carrier signal and a local voltage controlled oscillator. Phase demand→Ka→F(s)→K/s→Phase output F(s) =...
  42. K

    Detector Characterization Uncertainty -Poisson

    Hi to all, I have the following problem: I want to characterize two lots of detectors in order to retrieve their mean cross section and standard deviation for a proton beam. For cross section I mean the number of counts respect the fluence of particle (fluence = integral of the particle flux...
  43. A

    Dead time for radiation detector

    Hi, Iam working with a High purity Germanium detector and have an issue with the dead time. I let the detector do a background measurement over the weekend, about 55h. When I checked the measurement 60h had passed and the measurement was not finished due to dead time about 20%. At the start...
  44. M

    Stern-Gerlach experiment with orthogonal spin detector

    Suppose we have a Stern-Gerlach apparatus through which we send spin-1/2 particles and subsequently measure their position. If a passing particle "collapses" to the spin up state about X, it moves "up" and is registered by detector U, otherwise it "collapses" to the spin down state about X and...
  45. Saitama

    Sound waves - Detector and a moving wall

    Homework Statement A sound source, detector and a movable wall are arranged as shown in the figure. In this arrangement detector is detecting the maximum intensity. If the speed of sound is 330 m/s in air and frequency of source is 600 Hz, then find the distance by which the wall should be...
  46. M

    TV Licence Inspectors: How Can They Tell What You're Watching?

    Can these TV Licence inspectors actually tell if a person is watching TV in their home? They even claim to tell what channel a person is watching. If so, then how exactly do they do it?
  47. jssamp

    Zero voltage detector circuit

    I'm trying to build a simple circuit to detect when a lamp (tail light) is burned out, and light an LED in the dash. I think I can use a couple op amps but not sure how. My plan was to connect non-inv input to the (-) lead of the lamp socket and the other input to chassis ground. But I...
  48. D

    Where to find an alpha radiation silicon detector? (alpha spectroscopy)

    I am looking for an alpha detector to do an alpha spectroscopy (and maybe beta as well). The rough setup is a vacuum tube with a detector in one end and a source in the other, possibly with a magnet in the middle. I have googled around, but my problem is that I don't really know what is...
  49. tony873004

    Can iPads be used as motion detectors for AP Physics labs?

    I'll be teaching an AP Physics class in a few weeks. Usually labs are equiped with lots of desktop computers, to which I can add stuff like motion detectors: devices that can input velocities into the computer. But my lab doesn't have computers. Rather, each student has an iPad. This...
  50. A

    Unruh effect and energy imparted to a detector

    Hi all, One more question about the Unruh effect, i.e., that an accelerating observer will see a vacuum filled with particles in thermal equilibrium (a warm gas) where an inertial observer would see zone. If I have a detector moving with constant acceleration, how would I go about...
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