Hot answers tagged

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It just shows that the item is a meter. The arrow represents the indicator on analog meters.


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If your phonograph cartridge uses a piezo-electric pickup, the cartridge may have acted as a rudimentary crystal radio receiver. In a piezo-electric pickup, the stylus contacts a crystal and creates an electric current while jiggling as it moves through the grooves of a record. It's likely that while you were jiggling the apparatus, you found the exact ...


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Ionizing radiation loses energy in matter by creating electron-ion pairs. Suppose you have an 1 MeV charged particle stopping in a silicon crystal. The first ionization energy for free silicon atoms is about 8 eV. The ionization energy will be a little different for silicon atoms on the lattice, but not grossly so: your 1 MeV charged particle is going to ...


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According to the Review of Particle Physics (Section 33.7.4 of the 2014 edition) there are two main causes of radiation damage for electronic devices: Bulk damage due to displacement of atoms from their lattice sites. This leads to increased leakage current, carrier trapping, and build-up of space charge that changes the required operating voltage. ...


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can't that internal resistance be measured quite easily? No, it cannot always be measured quite easily as it can be very small. Now, if it's so small, why do we care? Well, we normally use a 4-terminal measurement precisely when the resistance we're trying to measure is itself rather small. If we have some uncertainty in the value of the probe ...


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I think it might be one of those things where people do something because everybody does. I agree with you, a figure of merit that includes noise would make more sense. But, as the circuit designer that I am, I could also say that that wouldn't be the end of it. For example, in the classic trans-impedance amplifier used for these kind of detectors the ...


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As you mentioned memristance governs nonlinear behavior of electric or magnetic circuit based on the amount of electric charge which has passed through it. In this paper Strukov et al. from HP labs described properties of memristors and provided fundamental mathematical model. As a physical model they employed metal/oxide/metal circuit where metal is Pt and ...


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The answer is not simple. The sensor you linked has 4 independent photodiodes, each with its own optical filter, and each gives a different result. In a perfect world, the 3 color sensors would exactly cover the overall spectrum of the white sensor, with no gaps or overlaps. AND the responsivity of each color sensor would be exactly the same as the white ...


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It is not that the interviewee experiences a longer delay - but that you see the whole scene delayed by the same amount. Delays are caused by a number of factors: sound is conveyed in packets that are digitized, compressed, and converted at various points along their path: at each point they experience at least "one packet's worth" of delays (can't send ...


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Even in a 'DC' circuit, diodes can be useful for, e.g., current steering. Consider a rudimentary battery backup system: When the primary 14V supply is present, the LED is on while D2 and R2 prevent the battery from charging at too high a current. When the primary 14V supply isn't present, D1 'disconnects' the LED and regulator IC from the battery while ...


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I believe that the reason may be at least two-fold: (1) For dopants to be effective, the energy level introduced by the dopant has to be a shallow energy level, not a deep energy level. A shallow level means that the impurity level is very close to the valence or conduction band, so it is easy to thermally ionize the dopant atom and have its electron (or ...


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From your question is sounds as if you understand how parallel LC circuits work, in which case it's easy to explain how an LC circuit works as a tuner. Any particular parallel LC circuit has a natural resonant frequency. If we assume the LC circuit is perfectly lossless, then if we apply a driving voltage at the resonant frequency the energy stored in the ...


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Yes, oscilloscopes will eventually wear out. They last a long time, if they are taken care of. There are many vintage scopes out there that are 30+ years old that still work perfectly. Here are a few examples of failure modes. There are probably more. 1.) Phosphor coating on the inside of the tube wears out, causing the display to dim. 2.) The tube develops ...


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The current in other Optoelectric devices like LED and photocells are flowing from a source of voltage to the devices but in case of solar cell, current flows from the cell to the load and thus current in circuit is taken to be in opposite ( or negative direction ). The voltage is still positive. Therefore, the fourth quadrant. Someone else may provide you ...


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As a Physics student I've found really useful Jacob Millman's Microelectronics, which offers a thorough insight into the world of Electronics, both digital and analogue. It covers a wide range of topics, from semiconductors to transistors (BJT, FET - both MOSFET and JFET) to operational amplifiers, with chapters devoted to the explanation of the concept of ...


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A capacitor can contain a certain amount of charge for a given voltage: $$Q = CV$$ When you have more than one capacitor in parallel, they have the same voltage (because they are in parallel), and each stores a certain charge. The total charge (at a given voltage) will be the sum of the charges on all the capacitors. Now if you have a certain load (for ...


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Electronics is mostly insensitive to static magnetic fields of that strength. The only serious damage that I would expect for electronic circuits is to switching power supplies (and circuits that are being powered by it) in the case that an inductor core gets saturated. In practice I have been debugging electronics for something like 40 years and I have not ...


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If you take a diode that isn't connected to anything we get the usual depletion layer at the PN junction: And we get a potential difference generated across the junction. Suppose we now connect the two side of the diode with an external wire, then a second depletion zone develops at the connections with the wire: And this depletion zone has a potential ...


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Electrons and holes occupy their states according to the Fermi-Dirac distribution, which has a single parameter $E_f$, the Fermi level (assume a fixed temperature). Provided $E_f$ is in within the band gap and far from the band edges, the (energy integral of) Fermi-Dirac takes an exponential form $\propto e^{E_f}$ for electrons and $\propto e^{-E_f}$ for ...


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Art of Electronics, now in its 3rd edition by Horowitz and Hill has always been a classic. Comprehensive and easy to read with an emphasis on practice rather than deep theory. I am a professional electronics engineer and I have used it (I transitioned from physics) for decades


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The answer suggesting "Art of Electronics" is spot on -- no argument. However, it is also spot on expensive. An alternative is Practical Electronics For Inventors which is now in its 4th edition and an excellent low priced book that allows you to move through the material more quickly. The scope of coverage for "Practical Electronics For Inventors" is ...


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But I wanted to know whether we can charge a capacitor while it is in use If, by "while it is in use", you mean while the capacitor is discharging, i.e., energy is flowing out of the capacitor to some load, then the answer is no since, by definition, if a capacitor is charging, energy is flowing into the capacitor. Put another way, a capacitor cannot ...


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Several points to add to @SamuelWeir's answers. Here I will focus on data for silicon, but the general principles apply to other semiconductors. First, plots of dopant energy levels are fairly common in semiconductor physics books. My copy of Sze, Physics of Semiconductor Devices, has it as Chapter 1, Fig. 13 on page 21. For silicon, the shallowest donors ...


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Answering this question properly would be just copy-pasting text book, so I'll be brief. $n_i$ is the intrinsic carrier density. Intrinsic means without doping. In an intrinsic semiconductor, concentration of holes equals to concentration of electrons due to charge conservation. The equation is called mass action law. The top of the valence band and the ...


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For an intrinsic semiconductor the mechanism for conduction is the thermal excitation of valence band electrons: $$ v \rightarrow e + h \tag{1} $$ So the number of conduction electrons and holes must be the same: $$ n_e = n_h = n_i $$ where the symbol $n_i$ is just the number density of carriers in each band i.e. the number of electrons in the conduction ...


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No it is completely different from tunnelling. Tunnelling is not possible in the classical limit, ballistic transport is! Ballistic transport is, as text says when the motion of the electrons is approximately following the classical laws of motion. That is, their mean positions fly through the lattice like balls through the air. This happens, as the quote ...


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this is a hand-wavy kind of answer that will probably get down-voted. the collector-base junction is normally reverse-biased in a circuit where a BJT is used as a current amplifier. because it's reverse-biased the material on both sides of the junction are then depleted of charge carriers for the same reason a reverse-biased diode is. then, without charge ...


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In radar, chirp (LFM - linear frequency modulation) is used to stretch the pulse so that the received energy is large enough for detection while having a large coherent bandwidth commensurate with the desired range resolution. There are two ways of detection, the so-called "stretch processing" that is just a correlation receiver using a homodyne mixer, the ...


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I've developed a half wave rectifier circuit in LTspice and I've got the result as shown in figures. In first figure, the input voltage(V(n001)) is 400mV(frequency 20.5kHz), which is grater than the threshold voltage of the diode and the output voltage gives a half rectified pattern. But when I give the input voltage value 200mV, which is less than the ...


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But how can there be current without electron potential (voltage)? In the case where there is no resistance, current (once flowing) does not require any voltage to continue flowing. If you start a current flowing in a superconductor, then even with no applied voltage, it continues to flow. It doesn't take any force to keep a ball rolling if there is ...



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