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.

View More On Wikipedia.org
  1. I

    B Beam splitter, one photon, one detector?

    I would like to know the results of a few scenarios with a beam splitter. (1) You send a single photon through a half silvered mirror with a reflector at either side, as above, but instead of having two detectors, and a 50% chance of either going off, you just have one detector, and where...
  2. V

    Touched a smoke detector and then put hands in mouth?

    Hi. I have a very embarrassing question to ask. I was changed the battery in my smoke detector, which is the sort that uses americium to work. I have a bad habit of chewing and swallowing my nails, and also picking and my nose and swallowing the stuff from my nose, too. I'm paranoid that I...
  3. ORF

    Misc. DIY muon detector -- Is it really working?

    Hello I found this video on YouTube, It seems that most of the counts are noise of the PMT... Thank you for your time. Regards.
  4. A

    High purity Germanium detector design related clarifications

    Hello everyone, I am Ashish, a mechanical engineering graduate from Arizona. I am doing a case study on some of the design related flaws in a high purity germanium detector. The information and pictures that I am posting is of an old detector from one of the manufacturers and it is currently...
  5. ryanuser

    Can a simple metal detector be modified to detect pipes at a higher voltage?

    Hello, I am a civil engineering student undertaking a project to investigate the effect of pipes and pipelines beneath the ground on the urban city environment above. In order to proceed I am designating a simple metal detector. Due to low depth capability of all commercial metal detectors mine...
  6. kostoglotov

    Can a basic envelope detector demodulate a DSB-SC signal?

    ie: http://m.eet.com/media/1072296/RFFig84.jpg I am 99% sure the answer is: no, it can't. I've read that DSB-SC demodulation requires the carrier frequency to be put back into the signal at the receiving end prior to demodulation (or as part of the demod process), and that if its too out of...
  7. D

    How to Design a Microvolt Pulse Detector Circuit with High Gain and Low Noise

    I am currently working on a small personal project to design a few circuits. I am trying to built a circuit that can detect 100 uV pulses with a pulse width of about 10 uS. I'd like to boost the voltage to a value readable by an FPGA (let say ~2 volts). I'm currently thinking about the...
  8. T

    B Exploring Entanglement in the Double Slit Experiment

    In the double slit experiment , if one place only one detector around one slit, while leaving the other slit unchecked, the interference pattern vanishes. Does this show entanglement?
  9. F

    B What Are the Most Accurate Smoke Detectors and How Do They Work?

    What are the most accurate smoke detectors have you come across and can recommend and why? Are there different types of detectors (I want to avoid the radioactive ones but are others less accurate)?
  10. S

    I Count Rate of a Detector in Scintillator

    Hello! How is the count rate of a detector defined (I need for a scintillator)? It is just the number of particle hitting the detector per second times the efficiency of the detector at that energy?
  11. Auto-Didact

    B Can Phonon Excitations in BECs Revolutionize Gravitational Wave Detection?

    Ivette Fuentes and her group are attempting to use phonon excitations in BECs to detect gravitational waves. Their GW-detector is called MAGA, which stands for Micrometre Antenna for Gravitational-wave Astronomy. Here's a video of her explaining it: More from their blog:
  12. O

    Why Does Amplitude Not Matter in Positive Sequence Detector Circuits?

    Hi, I am studying a positive sequence detector and have some trouble understanding it. I understand most of it, but the author in the book "Instantaneous Power Theory and Applications to Power Conditioning" writes: For extracting the fundamental positive-sequence voltage with the dual method...
  13. B

    Timing Resolution Required In Particle Detector

    Homework Statement A beam on Pions, Kaons and Protons, all with momentum ##\mathrm{P} = 10 \mathrm{GeV}## and negligible angular divergence travels ##100 \mathrm{m}## before hitting a target. What is the required timing resolution of the detector so that pions and kaons can be distinguished...
  14. DrClaude

    European gravitational wave detector falters

    http://science.sciencemag.org/content/355/6326/673?utm_campaign=toc_sci-mag_2017-02-16&et_rid=34818699&et_cid=1169695 Bummer :frown:
  15. rageoveralostpenny

    I Possible ways to increase particle detector resolution?

    So I'm doing some research for a physics essay on particle accelerators and I don't want to go into too much mathematical detail (as I haven't studied statistics or higher level Physics at school yet), but I have googled a lot of things and nothing seems to come up for methods scientists are...
  16. L

    Optical detector sensitivity at low and medium flux

    Dear all, This is my first post and I'm not sure if it's the right place to ask so don't hesitate to advise if necessary. I would like to know if it's possible that an optical detector (the complete system including sensor and front-end electronics) has a better sensitivity at medium flux than...
  17. A

    B When was the first double slit experiment done using a detector?

    When was it first experimentally seen that particle detectors can change the interference pattern effect expected in a double slit experiment? Is it still theoretical? What were some double slit experiments in the early era of quantum mechanics? How were they handled?
  18. G

    A What exactly is the detector of an ellipsometer measuring?

    Hi. I'm curious about how a PSA (polariser-sample-analyser) ellipsometer works, especifically the detector bit. In an ellipsomenter, light passes through a polariser which puts it into a known polarisation state. After that it hits a sample (which may be an interface, a surface or a thin film)...
  19. A

    Doppler effect (source and detector moving together)

    Homework Statement A source emits sound with a frequency of 860 Hz. It is moving at 20.0 m/s toward a stationary reflecting wall. If the speed of sound is 343 m/s, what frequency does an observer riding with the source hear? A 860 Hz B 913 Hz C 910 Hz D 765 Hz...
  20. C_Pu

    I How Do Silicon Radiation Detectors Work in Detecting Beta and Gamma Radiations?

    So we are doing Radioactivity lab at second year undergraduate. I am confused about the workings of the silicon radiation detects we are using even though the demonstrators tried to explain. We are detecting beta and gamma radiations by placing sources above a silicon detector that have a small...
  21. T

    Even and odd parity detector with active high/low inputs

    Homework Statement Using a single 74x138, build a 3-bit, active-low, odd-parity detector. (Y0-Y7 are selected by "b2 b1 b0" in binary. Also the nibble "0 0 0" is considered even parity) You may use one NOR gate and one NAND gate, with arbitrary fan-in(>1). Label input variables "I2 I1 I0" and...
  22. VxP

    Circuits motion detector light assembly 3 way proximity

    Is it possible to create a series of circuits capable of detecting a moving object with 3 levels of proximity e.g. green light when object is 10ft. away, yellow light at 5ft., red light at approx. 1ft. away, etc? Thanks, Dave
  23. Akmalidin

    Maximizing Battery Life: Using Load Droop to Detect Charge Level

    Hello, I am building a power bank myself and want to set put detector that determines the voltage level and indicates it in LED (4 LED are planned to be used). I know how to make it with transistors and op amp. But I was wandering if there is any IC chip that does it? Thank you, Akmalidin Alimov
  24. AndyWeb

    Electronics DIY BFO Metal Detector project

    Hello, I'm looking to build a metal detector. I shant get into all aspects of it, just the first for now. I have a BSc Physics so you can get mathematical if you want but not much electrical experience. I need an LC circuit to build a beat frequency oscillator metal detector. It should...
  25. Paul Colby

    B Toy GW Detector Model: "Hook Law Force

    A simple harmonic oscillator model consisting of two masses connected with a massless spring is provided in [edit] I hate cut and past on the mac. Always seems broken Slide 30 http://webs.um.es/bussons/GW_lecture_KG.pdf The left hand side of the equation of motion is simply the classical one...
  26. R

    How are the Electrical Connections of a Scintillator Detector Configured?

    Hell all, I need a help in understanding the electrical connection of a scintillator, a detector for detecting/counting gamma rays. In the back side of the detector there are three connections, 1. a high voltage supply, 2. to amplifier or preamplifier or single channel or multichannel analyzer...
  27. ChrisVer

    I Just how long is the ATLAS detector?

    A question that actually makes me laugh, but ... how long is the ATLAS Detector? Based on the ATLAS page here: http://atlas.cern/discover/detector the detector is 46m long. Based on references like here: http://arxiv.org/pdf/0910.3081.pdf the detector is 44m long. I wouldn't have asked this if I...
  28. ali khotbesara

    NaI detector in water source -- gamma & beta

    Homework Statement simulation of bersiv function of NaI detector it's in cylinder of water with volumetric source of Potassium40 (90% beta 1.31 mev & 10% gamma 1.504 mev ) how candefin define electron and gamma Volumetric source in mcnpx (6) ...
  29. Blidaru Bogdan

    A Calculating Primary Ionizations of Cosmic Muons in a Detector

    I am currently studying the MicroMEGAS detector principle. Ionizing particles traverse the space of around 6 mm of Ar:Co2 mixture in the detector (10x10cm2 x 6mm) like in the picture below. A cosmic muon (4GeV) enters this space and ionizes along its path. I assume the longest path it can take...
  30. ChrisVer

    A Track Reco in the Inner Detector of ATLAS

    I was reading about track reconstruction. So, I read about the "inside-out" and "outside-in" strategy for track reco. However both those strategies utilize information coming from the InDet parts... I know though, that the Muon Chambers are also used for the track reconstruction in ATLAS. How is...
  31. mrmrzamany

    Test Nuclear Radiation detector

    Hi, I want to test this radiation detector http://www.teviso.com/en/products/radiation-sensor-rd3024.htm The problem is we don't have strong nuclear radiation sources or even weak ones , can i mimic the radiation ?? For example can i use Microwave sources or RF field or other radiation sources...
  32. P

    Liquid Scintillation Counter w/ fast neutron detectin isotop

    I'm trying to make a LSC with U-238 (non-aqueous form) dipped in the scintillating cocktail to detect fast neutrons (no thermals or epithermals, only fast) from a Cf-252 source. How do I calculate the wavelength emerging from the cocktail (assuming U-238 does not react with the cocktail)? Also...
  33. A

    Non-contact DC Voltage detector

    How to build Non-contact DC Voltage detector/sensor?
  34. Madi Araly

    I QKD Question: Alice & Bob Detector Cross-Checking

    Hello, I've been learning about Quantum Key Distribution recently, but I can't seem to find the logic in one of the steps... maybe I'm just having a brain block. o_O So let's say Alice has sent a stream of entangled photons to Bob, and he finishes measuring them and is left with a binary code...
  35. N

    What causes secondary photons in He-3 detectors?

    Does all the signals detected by He-3 detector caused by neutrons? When the He(n,p)t reaction occurs, will proton cause any secondary x-ray photons since it de-accelerates in matter.
  36. J

    Can a 3V/m Electric Field Detector Detect Someone on the Other Side of a Wall?

    I bought this electric field detector that can detects minimum of 3V/m. It said the human body can emit electric field.. so the detector can detect the presence of someone on the other side of a wall. May I know how the human body can emit electric field.. and is a detector with a 3 V/m really...
  37. E

    Determining an error due to non point like detector

    Homework Statement Recently I have conducted an experiment using a gamma source (22Na) and a scintillation detector (NaI), at the start of the experiment one of the desired outcomes was to see that the intensity of the source fell off as 1/r^2. Seeing as the detector is not point like (I am...
  38. DetectiveT

    What radiation detector can tell energy level?

    Hello everyone. Is there a type of radiation detector that can tell the energy level? I have a basic understanding about Geiger counter and Scintillation counter, they seem only tell the incident particle number. The testing environment may contain Thorium series, Uranium series and Actinium...
  39. J

    Does a Modern Car Exhaust System Impact a Carbon Monoxide Detector's Accuracy?

    https://www.amazon.com/dp/B004Y6V5CI/?tag=pfamazon01-20 I bought the above carbon monoxide detector out of curiosity.. it has over 1,500 positive 5 star reviews. I put it near the exhaust in the mall parking and sit inside for 20 minutes.. but it doesn't seem to detect any carbon monoxide...
  40. xpell

    Truck-deployed nuclear reactors antineutrino detector: range?

    Hi! I was reading this article about the possibility of detecting removals of "double-use" fissile materials from a known reactor using an antineutrino detector deployed in a truck "that uses 20 tons or less of scintillator material (and) could be fit into a 6-meter shipping container and parked...
  41. J

    Electrical DIY Atmospheric Carbon Dioxide Detector?

    I thought it would be an interesting project to build a detector that will measure and log the outdoor atmospheric CO2 levels. These (global average) levels are currently about 400ppm and these (global average) levels vary by a few ppm every year. Looking for a sensor though, I can't seem to...
  42. P

    What Is the Error in Counting Rate Per Second for Gamma Photons?

    Homework Statement A detector is used to count the number of gamma photons emitted by a radioactive source. If the number of counts recorded in exactly 20 seconds is 10000, the error in counting rate per second is (a) 5.0 (b) 22.4 (c) 44.7 (d) 220.0 Homework EquationsThe Attempt at a Solution...
  43. P

    Homemade Cosmic Microwave Background detector

    Hi Guys, I studied physics for my bachelor but still I am not a super expert, although I am still working closely to physics (but not so much astronomy). I was wondering if it would be possible to build a radio, or some other devise (any ideas?) that could be tuned at the frequency where the...
  44. SpaceKidd_N7

    Delayed Choice Quantum Eraser: Am I missing something here?

    Hello everyone, I actually have three questions: 1. Am I missing an important detail in my understanding of how the delayed choice quantum eraser experiment is done? 2. How does one account for what takes place in the experiment without using the concept of "retrocausality" (effect before...
  45. Grinkle

    What is a gravity wave detector measuring?

    I am having trouble understanding how a gravity wave detector can be de-coupled from the wave it is intended to measure. For the sake of conceptual discussion, if I am eyeballing a ticking clock some distance away and a wavefront hits the clock and say 10 or so waves pass through the clock...
  46. Alan I

    Detector moving toward charged ring - rate of change of V

    Homework Statement A thin ring (radius r = 1.41 cm) carries a charge Q = 8.57 pC distributed uniformly along its length. The ring lies in the y-z plane, so the axis through its center is the x-axis . A small detector is moving along the positive x-axis toward the ring at velocity v = -0.543i...
  47. S

    Double Slit, Detector, Light -- Pattern?

    I have a question about how the double-slit-with-detector experiment works out with a beam of light. (1) When you fire electrons through the double-slit apparatus, it creates an interference pattern on the screen. (2) When you place a detector at one of the slits, the interference pattern is...
  48. M

    I Bell's Theorem: more general interactions with detector?

    [Mentor's note: split off from the thread https://www.physicsforums.com/threads/first-loophole-free-bell-test.829586/ as this is a general question about Bell's Theorem, not the specific experiment discussed in that thread] It says in the paper ... ... and the 'CHSH-Bell inequality' all...
  49. Garlic

    Size of Americium in a Smoke Detector

    Hello, A few days ago I tried to calculate the decay heat of Americium in a Smoke Detector, but as I was trying to find the volume it should have, my calculations showed that its volume should be really small (smaller than a cubic micrometer), but it was obvious that it couldn't be so small...
  50. P

    Why can't I test a smoke detector with smoke?

    I just came across the user instructions for my smoke detectors and am surprised. I've attached a small section of the instructions. They're from a mainstream manufacturer and labelled with a British Kitemark. You can see that I'm not supposed to test it with flame, smoke nor heat, and the...
Back
Top