What is Bias: Definition and 151 Discussions

Bias is a disproportionate weight in favor of or against an idea or thing, usually in a way that is closed-minded, prejudicial, or unfair. Biases can be innate or learned. People may develop biases for or against an individual, a group, or a belief. In science and engineering, a bias is a systematic error. Statistical bias results from an unfair sampling of a population, or from an estimation process that does not give accurate results on average.

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  1. 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...
  2. ryanj42

    Tug of war weight bias vs seated tug of war

    I saw a thread previously created but locked, and I do understand many events like the tug of war, and wrestling have a huge bias to weight. 100kg guy vs 70kg guy. The 100kg guy only needs to push around 70kg and visa versa. I do understand the 70kg guy could be stronger, but generally speaking...
  3. 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?
  4. baby_1

    MOSFET Bias Circuit and Equations

    Hello I'm starting to design my amplifier with Mesfet.I calculated my stable amplifier with scattering parameters,however I don't know how do dc bias because I don't have any dc equations for Mesfet and and I can't extract dc information from datasheet (because datasheets only define IDSS...
  5. R

    Bias voltage across a tunnel gap

    Homework Statement Homework Equations See below. The Attempt at a Solution This is only a 1 mark question so I'm probably missing something really simple but I just can't figure it. Below is the slide we have been given: Does anyone have any ideas?
  6. golphan

    IMU-Gyro Bandwidth and Sensor Fusion on Performance

    Hello, For my Master's Project, we are to choose an IMU module to stabilize a platform. You can think of a servo actuated turret, mounted on a Stewart Platform(which will generate the disturbances). The angular position error should be very low and there are both high and low frequency...
  7. H

    Is E-field in pn-junctions changing linearly with bias?

    Hi guys, there are a lot of textbooks and articles describe the electric field in depletion region at thermal equilibium, but very few of them tell what happens to the field under bias. I am wondering if the electric field in the depletion region simply changes linearly with reverse bias? Or if...
  8. P

    Creating Matter from Photons: Proton-Antiproton Bias?

    Given sufficient energy a proton/antiproton pair can be created from photons in the laboratory. Does the (apparently) slight bias exhibited in the big bang apply to the laboratory? In other words, the universe is seemingly not made of antimatter, only "matter." Pushing this idea further, is...
  9. H

    Finding the bias of a random sample

    Homework Statement In a study to estimate the proportion of residents in a city that support the construction of a new bypass road in the vicinity, a random sample of 2025 residents were polled. Let X denote the number in the sample who supported the proposal. To estimate the true proportion in...
  10. L

    Engineering Designing a Bias Circuit for BJT with Optimal Ratio and Voltage Drop

    Homework Statement It is required to design the bias circuit as shown in figure for a BJT whose nominal {\beta} is 100. a.) Find the largest ratio {(R_B/R_E)} that will guarantee {I_E} remains within 10% of its nominal value for B as low as 50 and as high as 150. b.) If the resistance ratio...
  11. B

    Voltage follower bias current (opamp)

    So in the input of this buffer circuit I have a small AC signal (μV) that is capacitively coupled to an op amp. What is the role of R? I read that it is to provide a bias current path and it has to be large in general but I can't understand it. Any help much appreciated
  12. S

    N type semiconductor under voltage bias

    I plotted n type carrier density vs temperature plot at zero applied bias and the intrinsic carriers dominate the extrinsic carriers at high temperature, now I wonder how plot changes if I apply positive bias to this semiconductor. Does intrinsic carriers dominate the others at lower temperature?
  13. P

    Selection bias with respect to potentially apocalyptic events

    Note to moderators: I’m not sure if this topic is mainstream enough for the forum. If you decide to remove it, I’ll understand. Not convinced I've put it in the right section either! I’m sure you’re all familiar with, or will easily understand, survivor bias, which is a form of selection...
  14. A

    Law of the PN junction under forward bias. Valid ?

    I'm currently studying the physics of the PN junction. I went though the derivation of the built-in potential in the PN junction under equilibrium: Diffusion current density = Drift current density D_{p}p\frac{dp}{dx} = EU_ppq where D_{p} : Diffusion coefficient for holes p = holes density...
  15. ranju

    Explain Vceq & Icq in Collector-Base Bias Config.

    the base resistance in collector to base bias configuration is given by Rb=Vcc-Vbe-IcRl / Ib now , in a question only the value of Vceq is given & they found Rb as Rb=Vceq/Ib.! what is Vceq over here..?? and another quantity Icq is used..what are these two quantities..please explain a bit..
  16. ?

    Calculating Emitter Current - Voltage-Divider Bias

    I am aware that there are two methods of working out IE for a Voltage-Divider circuit. The first is...
  17. S

    Voltage Divider Bias: 4 Resistors, Base/Emitter, Collector, Stabilization?

    why do we need 4 resistors?we are applying voltage across base emitter junction.Why do we need a resistor for collector side.One more thing how does the resistor across emitter provides stabilization?
  18. T

    Alternative to Von Neumann bias correction method

    Hi I have discovered that the Von Neumann bias correction method only works when the bias is 100% stable, for example tossing the same loaded coin again and again. Does anyone know of a bias correction method which can correct an unstable bias? Is this impossible? Edit: Let's say I have a...
  19. S

    Maths of carrier densities in p-n junction w/ bias.

    Hi, I'm trying to recreate some formulae of my professor's but I'm hitting a dead end. Starting with the following equation for the electron carrier density in the conduction band of a semiconductor: n = N_c exp(\frac{-(E_c - E_f)}{kt}) N_c is just a constant, E_f is the electron...
  20. A

    Adding Bias Voltage to HV Generator - HV Circuit Solutions

    Hello all. I have a HV generator that puts out ~200 nsec, 10 kV pulses. I'd like to add a bias voltage to this but I'm not sure how this is normally done. If I add a parallel DC source I could use a diode to protect the DC source from the kV pulse, but I can't seem to find kV rated diodes that...
  21. Jalo

    What is the MOSFET bias point?

    Homework Statement Given the following circuit find the bias point (VDS,IDS). Homework Equations The Attempt at a Solution The first thing I did was find the value of VG, the voltage from the gate of the mosfet to the -VDD source. VG = VDD * R2/(R1+R2) To find the...
  22. H

    Exploring the Effects of High Forward Bias on a P-N Junction Diode

    What would happen if forward bias in a P-N junction were more than built-in potential? Could we reach to this situation practically?
  23. Hyo X

    Can Tunneling Occur at 0 Kelvin with an Applied Bias?

    Hypothetically: A pair of electrodes with a small insulating barrier between them. Transport is via tunneling through the barrier. You apply a small bias, and measure conductance because there is tunneling current. At 0 K, can there still be tunneling? Is it possible for a tunnel junction...
  24. L

    Bias of an estimator: Can you confirm that I am doing this right?

    Let X_{1}, \ldots, X_{n} \; \mathtt{\sim} \; \textrm{Poisson} (\lambda) and let \hat{\lambda} = n^{-1} \sum_{i = 1}^{n} X_{i}. The bias of \hat{\lambda} is \mathbb{E}_{\lambda} (\hat{\lambda}) - \lambda. Since X_{i} \; \mathtt{\sim} \; \textrm{Poisson} (\lambda), and all X_{i} are IID...
  25. P

    Question about op amp input bias current

    Hello, I have been researching operational amplifiers because I plan on using some in a circuit I wish to build, but have been stuck for awhile on the concept of the maximum current that can be handled by the non-inverting input. It appears as though the input bias current is the current...
  26. D

    Difference between Voltage Bias in STM/STS vs. Electrochemical Cell

    Hello Everyone, I am a student studying electrochemistry – specifically energy storage devices. I have been familiarizing myself with various techniques to characterize the electrode surfaces. In particular, I am interested Scanning Tunneling Microscopy (STM) / Scanning Tunneling Spectroscopy...
  27. D

    How to set up equations to solve for v_os and input bias current?

    Homework Statement A particular inverting op-amp has a gain of -100 V/V, and an input resistor 100 K. The output voltage is 9.32 V when measured with the input open and has a 9.10 V. when measuring with the input grounded. What is the input offset voltage and bias current? The circuit is...
  28. P

    How to combat misinformation and bias on the internet?

    On the web I find misunderstandings of a scientific result, clear bias, and obviously wrong information. For subjects close to my expertise, I can identify the errors. Subjects outside my expertise are not so easy: I spend hours surfing the web to try to verify a single statement, and often...
  29. E

    Is there an age bias in physics?

    I'm 27 years old and I recently quit my job to go back to school for physics. I just finished up my first semester and I'm about to start the Summer semester (I'm technically a sophomore though, even though I'm just starting, because I do have transfer credits). I have to do a few different math...
  30. S

    How to avoid DC bias on output?

    I designed the BJT amplifier below. After substituting in for the values of the actual resistances measured in lab, I reran the simulation. The hand calculation I derived for the gain was nearly spot on with what I was seeing in Multisim. Now, when in lab I get approximately the same value I...
  31. S

    Adding a 2V DC Bias to AC Mains

    Need to do something which requires adding a 2V DC bias to power coming out of the wall (120V, 60Hz), going to a motor. Basically need the 2V DC bias across the motor windings. Motor windings have about a 10 ohm DC resistance. I have a DC power supply that has a max voltage of about 50V...
  32. E

    Metals and semiconductors at high bias

    Hello, Is there a well known theory on how metals and semiconductors should behave, electrically, while under a high voltage bias? Say, 2-3V? For example, how does the conductivity change as a function of voltage bias as we go from the low bias regime into high bias? Is there a linear...
  33. C

    Understanding Bias in Semiconductor Devices

    Is there not a difference between bias as in "A diode is forward/reverse biased" and establishing the terminal voltages/currents needed to bring say a transistor to the quiescent point? Just curious
  34. W

    Forward bias in a silicon p-n junction diode

    Homework Statement The forward bias current I in the diode described (silicon p-n junction) varies as a function of the voltage V and temperature T described by the formula I = I_s*|e^[(|e|*V]/[n*k_b*T]) - 1| where |e| is the fundamental charge, k_b is the Boltzmann constant, I_s is the...
  35. E

    What is going on when a solar cell goes into reverse bias?

    I would like to understand exactly what happens when a PN doped crystalline silicon cell is shaded.Lets assume we have ten solar cells wired together in a series string.That there is plenty of sunlight on the first nine cells but cell ten is completely shaded.Lets say the forward bias of each...
  36. C

    Self Bias Transistor Design Problem

    Homework Statement I have to solve for RD, RS1, and RS2. Homework Equations AVNL=-mg(Rd//rd) Vdd-Id(Rd+RStotal)=0 Bias Line Eq: Vg-Vgsq-Idq(RStotal) The Attempt at a Solution I have solved for RD by using the AVNL equation and the given value of -8 for AVNL. I found RD to be...
  37. R

    CLIPPER CIRCUIT to clip of higher voltages without bias

    Good Day everyone. Is it possible to design a clipper circuit to bias at higher voltage level without using bias voltage? For example. to clip at 3.5V for a input signal of 10V sine without using a BIAS VOLTAGE??
  38. G

    Football referees and Confirmation bias

    So for those of you who like football, you have undoubtedly heard the calls from media sources that the debacle in the Packers-Seahawks game was the final straw proving that the NFL has to find a way to get the regular referees back on the field. While I agree that monday night was a debacle...
  39. S

    Physics Gender Bias in Particle Physics?

    Hello, I'm not sure if there's a post for this already, but I'm in high school and I would like to go into the physics (or mathematics) field. I am especially interested in particle physics at the moment. My mother has her masters in math, and she's told me some tales about her experiences...
  40. A

    Calculating transistor bias currents

    Homework Statement http://img846.imageshack.us/img846/955/29278644.jpg The Attempt at a Solution Basically I want to know whether my working method was correct as I have doubts with some of it. I first did voltage division at the two base resistances, and I get 3V at the base. Since we know...
  41. zoobyshoe

    Uncovering the Bias: Can We Recognize Gay Faces from Photos?

    http://www.telegraph.co.uk/science/science-news/9269298/Women-really-do-have-a-gaydar.html My question: what photos were shown, and do they demonstrate a confirmation bias in selecting only masculine looking women as the lesbian examples? A couple weeks ago I was going through my pictures...
  42. O

    Rearranging equation to find back gate bias

    Hello, I am having a bit of an issues rearranging an equation for my solid state electronics class. I seem to have a mental block with this sort of stuff, so I am hoping someone can help. The equation is 0.34 = 1.05((0.64 + |VBS|)1/2 - (0.64)1/2) I know the usual stuff, like + to a -...
  43. S

    Exploring Primes: Is 'Pair of Factors' Bias?

    --> Why are prime numbers so important to number theory? (Apart from speculations of being connected to energy levels of complex quantum systems.) --> Let for time being, primes that we know of, be called primes of "type-2". Here '2' comes from the definition of primes. Since we consider...
  44. H

    Why photodiode is operated in reverse bias?

    why photodiode is operated in reverse bias?? can anyone please explain why photodiode is operated only in reverse bias?? can we operate it forward bias state also??
  45. L

    BJT voltage divider bias beta variation

    Homework Statement Given, β=100, Is = 6E-16 See attachment. a) Find min value of Rb such that the BJT is in active region b) For the Rb found, what is the base-collector voltage if β=200 Homework Equations The Attempt at a Solution Assuming, VCE min for active region operation...
  46. S

    Estimation, bias and mean squared error

    Homework Statement (x1,x2,...xn) is modeled as observed values of independent random variables X1,X2,...Xn each with the distribution 1/θ for x in [0,θ] and 0 otherwise. A proposed estimate of θ is m = max(x1,...xn) Calculate the distribution of the random variable M=max(X1,X2,...Xn) and...
  47. L

    What is the impact of the beta dependence on a BJT with voltage divider bias?

    For a BJT with voltage divider bias (but without emitter deneration resistor), what is the beta dependence? Ib is (Vth-Vbe)/Rth [where, Vth and Rth are thevenin equivalent of the divider) Ic = β * Ib The above is almost same as just base bias, where a resistor from base is collected...
  48. Ivan Seeking

    Writer bias in books, TV, movies, and theater

    Tonight I was watching Stephen King's Bag of Bones and noticed a common motif - a famous author moves to a small, remote town, and encounters X. What caught my attention wasn't the weird, small town motif [I can relate to that one! :smile:], it is that so often the main character is a writer...
  49. G

    Input Resistance & Bias Currents: Explained Simply

    If it is in inverting or non-inverting configuration, will the input resistance increase the mismatching of the bias currents, or will it only increase the error voltage? Please Explain like your talking to an idiot, I need to write an essay on this, and I don't know what to do! Also how...
  50. Z

    Reversed bias diode with applied voltage

    hi there i just have a question about diodes say for example we have the following cct: the circuit with the diodes with the 5V supply, one of the diodes is on and the other off and i understand why this happens but when dealing with the circuit the opamp and the diode i am confused. the...
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