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. .Scott

    B Canadian Antineutrino Detector detects Nuclear Power Plants from 240km

    The SNO+ Experiment in Canada is still in development, but analysis of early antineutrino detections as published in Physics Review Letters and as referenced in the SNO+ results page are believed to be from appear to be the from Ontario reactors 240Km away.
  2. Philip Koeck

    A Characterizing Electron Beam w/ CMOS-Camera or Faraday Cup

    I want to characterize an electron beam using something like a CMOS-camera or maybe just a Faraday cup. The electron energy is between 1 and 10 keV and the expected total current around 10 microA for 1 keV electrons. Essentially I want to see whether the beam diameter is around 1 micrometer...
  3. M

    B Why doesn't the detector affect the result?

    Why doesn't the detector effect the result of the double split experiment
  4. engnrshyckh

    Object detector using ultrasonic sensor with 555 timer

    See the attached figure. I used 220uF with buzzer and also tried 10uF capacitor but buzzer isn't loud enough. I don't have any 3.3pf capacitor. I used 1.1 pF instead. I also tried changing the resistance of potentiometer but still buzzer isn't sound loud enough.
  5. M

    A MCP detector resolution

    Hello! If I want to model the time and spatial resolution of an MCP detector, should I use a gaussian or a uniform distribution? I imagine that, for example for the spatial distribution, the uncertainty is given by the size of the pixel on the detector, which makes me think that uniform...
  6. Joshy

    Engineering Equivalent resistance of an envelope peak detector (RF CMOS)

    Full problem: I don't normally think about circuits like these in terms of energy (Joules) so I was very much confused. What I did was find where the simplified expressions intercepts with each other to get the voltage. I scanned in my work although this text is a walk through of what I did...
  7. B

    InfraRed Detector Mystery (but not Elementary....)

    Hello! I found this circuit element below in a drawer marked "IR detectors" (which I must have written on it myself, a long time ago...although I must admit don't remember doing so #OldAge). First of all, I'm trying to figure out what, exactly, it is. My initial assumption was that it looks...
  8. Oldman too

    Apple AirTag detector for Android

    Cool open source Air tag detector here. From, https://www.bleepingcomputer.com/news/security/free-android-app-lets-users-detect-apple-airtag-tracking/ https://arxiv.org/pdf/2202.11813.pdf
  9. Dinarchik

    Alien spaceship wormhole gravitational waves detector

    Recently viewed video about wormholes that required negative energy to create it. Suppose hypothetical aliens have discovered this technology. Spaceship enters in first point and exit at second. To prevent spaceship destruction they might have technology to smooth gravitational waves on exit...
  10. R

    B Where can I buy a muon detector?

    Hi, Can you please help find where I can buy a muon detector, or someone who will build a muon detector for me? Nothing fancy just a detector that flashes and beeps when a muon is detected. I do not have the skill or knowledge to accomplish this task. Any help with this endeavor would be greatly...
  11. gxa

    Measurements with the CsI(Tl) detector

    I made an experiment in the lab. I took some measurements with the CsI(Tl) detector by placing the cobalt at a distance of 5 cm. I have attached the measurement result. I need to find the count for the peak energies. How can I do it? Any idea?
  12. A

    B Source radioactivity estimate from a radiation detector

    If I have a source of radioactivity that is concentrated instead of evenly spread out, like a "tablet" source instead of a evenly distributed aerosol/dust on ground for example then is it possible to even estimate the total number of disintegrations (Becquerels per second) by measuring the...
  13. G

    Photon and Neutrino detector and photon trawl device

    Summary:: Hello I am a writer and presently working on treatment for a science-fiction story. So I am not a scientist, just a neophyte interested in science and wanting to write a fiction that would not be too far-fetched and that would make some sense for everyone, including the scientific...
  14. B

    A Single photon avalanche detector (SPAD) difficulties with photometer

    I have been developing a SPAD based photometer having a 10 ns deadtime, near-zero dark counts, near-zero afterpulsing, and that is temperature independent (within a reasonable range). It works well with photon level pulsed optical signals, (10ns to several microsecond pulse widths at rates up...
  15. S

    B Planck Length 1 Detector? Emitter?

    Do we have the ability to detect the gamma ray of Planck Length 1? Is there any known phenomenon, natural or man-made, that could emit on Channel 1? How dangerous to man and machine would Channel 1 be / at what density (is that the right term?) would it become dangerous? Would there be any...
  16. S

    Radiation from smoke detector

    Recently when cleaning, I opened the cover of our ionisation smoke detector and as I was touching all around the inside of the smoke detector with my bare hands and most importantly including all the sides of the ionization chamber with the radiation symbol on it which contains the radiation...
  17. A

    A Standard radionuclides used in energy detector calibration

    In using scintillator or germanium energy sensors, certain radionuclides representing some definite line energies are used to calibrate the sensors. What technique or method is used to measure or determine the energies of these standards.
  18. A

    B Radiation detector types/physics

    While watching the MIT online opencourse videos about ionizing radiation physics some questions came to mind. Let me first clarify and reinforce some basics by asking them to you. I understand this might be long, please forgive me. I will appreciate your time. 1) A GM tube consists of a chamber...
  19. J

    I Valentine Monopole & Detector Constructions

    Here is a high quality article about it written by Ethan Siegel, with Ph.D. astrophysicist, author, and science communicator, who professes physics and astronomy at various colleges and has won numerous awards for science writing since 2008. So it's not a crackpot source. The Enduring Mystery...
  20. Wrichik Basu

    Zero crossing detector for Arduino using 4N35 optocoupler

    I am designing a zero crossing detector for Arduino using the 4N35 optocoupler. This is just a small part of a large project. I haven't bought the components yet, so do not ask me for readings. Everything is in the planning phase now. My input will be a 6-0-6 transformer (220V to 6V step down)...
  21. A

    I Building a muon Cherenkov detector

    So far I have an R928 Hamamatsu pmt from ebay, that I believe will be good since it has UV glass, and the majority of the photons should be in the UV range. I also have an old Brandenburg pmt HV power supply but need a BNC connector to use it. I already have a good rigol oscilloscope. Soon I...
  22. i_hate_math

    Radiation detector - cylindrical ionising chamber

    Let r = position of the electron = 6mm - 36.8μm; λ = mean free path traversed. Integrate E(r) = Q/(2πϵLr) between the two shells gives: V = [Q/(2πϵL)]*log(r/(r-λ)) I know that the question is asking for the voltage at which the electron energy will get to 23eV, but i am unsure how to get rid...
  23. lottotlyl

    Engineering Calculate R and C in Envelope Detector Circuit (AM Modulation)

    1. Add impedance in parallel of capacitor and resistor Z_rc = 1/((-wC/j) + 1/R) = (jR)/(j-wRC) 2. Ohm's law for relationship of i_d, Z_rc, and Vo Vo = i_d * (jR)/(j-wRC) Unsure how to do the rest? Thanks.
  24. Dr. Courtney

    The Human Body as a Dark Matter Detector

    https://www.sciencedirect.com/science/article/pii/S0370269320301040#br0210 I need to give this more thought, but the ballistics section is pretty good, and I think their basic dE/dx argument is sound: If a collision at a ballistic rate transfers about the same kinetic energy to the human body...
  25. C

    Dash Photon detector

    My car aircon recirculation button often turns off by itself. I guess this happens when the aircon is cold enough. Problem is. When it turns off and the indicator light disappears, the pollution outside gets into my car and my pm2.5 monitor registers 20x higher. What kind of photon...
  26. N

    Suggestion for a gas discharge lamp

    There is a physics event being organized in my college for which I had planned to make a muon detector. I have the circuit ready which brings 240 volts ac mains source down to 80 volts dc supply. But now, I am facing a serious problem. I have been unable to find a neon glow lamp. Basically, mý...
  27. rumelote

    Electronics Radioctivity: radiation detector with an LED

    Hi I'm a student working on my last assignment in physics department. now I'm trying to make a radioactive radiation detector with the principle of ion chamber. i want to add some new mechanism which when a charged particle pass through the chamber, an LED would emit a light. is there any...
  28. W

    Have you been Pwned (Breach Detector)

    Hi, What do you all think of Firefox' breach detector: https://monitor.firefox.com/?utm_source=mozilla.org-privacy-products&utm_medium=referral&utm_campaign=privacy-products&entrypoint=mozilla.org-privacy-products ?
  29. D

    How to build a Raman detector?

    if you filter completely the relaigh scattering, could a solar panel detect a raman signal?
  30. J

    A Why do I need to move the detector in a Goniometer to 2-omega?

    Hola, I have a question to a Goniometer or more specific of a Bragg-Bretano- measurement, where you need to move your detector in die double angular speed then you move your Röntgen source. Why is it so? In my thoughts, it makes sense to move them in the same speed of the röntgen source and you...
  31. Buzz Bloom

    I Dark Matter Detector Observes Rarest Event Ever Recorded

    The URL below is from Rensselaer Alumni Magazine. It is about an unexpected observation of an xenon atom decay using the equipment designed for detecting dark matter particle interactions with xenon. https://magazine.rpi.edu/at-rensselaer/dark-matter-detector-observes-rarest-event-ever-recorded
  32. jdou86

    Can someone explain this GRE problem to me? (gamma ray detector)

  33. entropy1

    I Double slit and detector

    Suppose we have a double slit and we fire a photon through it with no photon detector at either slit. We get a interference pattern. Now we put a photon detector at the left slit. The interference pattern is destroyed, right? In this last setup, the photon can be located at the left slit. So...
  34. Graeme M

    B The Human Eye as a Detector in Double-Slit Experiment

    Trying to wrap my head around what the double-slit experiment is illustrating, it occurred to me that one could replace a mechanical detector with the human eye. I found that this was tested with what seems an elaborate test setup in 2016, and the result suggests that while an interference...
  35. G

    Ratio Detector question

    Hi, I built the attached ratio detector circuit and it works but I can't understand the reason for the connection marked in green. I need an explanation, please. Thanks in advance. GR
  36. Zeke137

    I New table-top gravitational-wave detector proposed

    The group is led by Andrew Geraci, an associate professor of physics and astronomy in Northwestern’s Weinberg College of Arts and Sciences . It would appear that the sensors employ optically-trapped microspheres or microdiscs, the positions of which can be measured to microns or better as these...
  37. CHOP

    I Double slit interactive detector

    my understanding is that there has never been a double slit experiment with a detector at the slit, where that detector's state was changed as a result of a particle being at that slit. if true, then if such a schema was possible and tried, then there would be no interference, and the reason...
  38. L

    How long does it take for the Magnetic Field to reach the detector?

    Suppose I had an electromagnet that would instantly go to full power when turned on (impossible) and at one light second away a detector capable of detecting the electromagnet. When I turn the electromagnet on how long does it take for the field to reach the detector?
  39. dRic2

    B Thought experiment -- A radioactive decay detector and randomness

    Take one radioactive element and put a detector all around it so that you can immediately detect whenever it will undergo radioactive decay. Have a clock connected to the detector to note the "exact" instant at which the atom decays. Let's say that after 3min after the clock started counting the...
  40. Isa

    I Question about noise in entanglement experiments

    Hi everyone While learning about quantum mechanics, I became curious about the real-life experimental data. Wikipedia says that entanglement experiments require coincidence counters, because the majority of the signal received by detectors is noise. It further says, that coincidence counters...
  41. R

    I Photon detector on a dual slit experiment

    My experiment is to place a detector on one of the slits in the dual slit experiment so That it would record or not the passage of the photon, and then reset the detector to its base state, Erasing the result. In such a case, would the interference pattern be destroyed simply because the...
  42. M

    I How does the inverse square law apply to a focused detector?

    I am interested in evaluating light intensity variation in a digital image. A colleague wants to apply an inverse square law correction to account for distance variation. I am trying to justify that in this case, the inverse square law does not apply. Treating each pixel as a detector, it has...
  43. M

    FM Ratio Detector is not working

    hi , please can somebody help me about this circuit, is not working i don't get audio signal here is my circuit rename in asc frm txt thanks
  44. N

    Calculate the power measured by the detector at distance h from the source

    Homework Statement An isotropic point source radiates electromagnetic energy, and its output is measured by a thin disc-like detector of radius R. Calculate the power measured by the detector at distance h from the source, assuming that the plane of the disc is orthogonal to the line of sight...
  45. A

    B Double slit experiment: What if the detector is removed quickly?

    Hi all! I'm a physics enthusiast and I've been reading/watching a lot of stuff about the double slit experiments. I was watching a youtube video about the delayed quantum eraser experiment and it was really interesting and got me thinking. So here's my question. What if the detector is placed...
  46. T

    Resolution of a semiconductor detector

    Homework Statement A novel semiconductor detector crystal requires an average energy of 1.8 eV to create an electron-hole pair, it has a Fano factor of F=0.2. Use this information to calculate the potential resolution for detecting a gamma-ray with an energy of 700 keV. Homework Equations...
  47. Cocoleia

    Position of particles on a detector after decay

    Homework Statement A hypertriton (a bound system with a L hyperon together with a deuteron core (proton and neutron) is produced at the origin of the coordinate, (x,y)=(0,0) with a velocity of 0.94c (beta=0.94), flying along the x-axis. The mass of the hypertriton is 2.991 GeV/c2 . It decays...
  48. Pickled_Gorilla

    Neutrons Falling on a Detector

    Homework Statement A collection of neutrons, nominally at rest, are confined in a region 1.0 nm wide on the x-axis at a height of 50 cm above a neutron detector. The neutrons are released and fall under the influence of gravity towards the detector which records the horizontal position of the...
  49. D

    Nuclear Reactor Rod Replacement Time

    If an enemy had a secret nuclear reactor and they were retrieving the rods, or whatever it is that they retrieve to make secret nuclear bombs, how much time (how fast) would it take for them to retrieve their needed material? Would just a part of the reactor be shut down, and if so, what...
  50. Kara386

    Particle track detector to measure the charge of a particle

    Homework Statement The detector is made of two co-planar layers of silicon two metres apart, and there is a plane of wire chambers halfway between them. The wire chamber can measure a track with precision ##100\mu##m. What is the highest momentum a particle can have for which the detector will...