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Assuming that each sensor sees only the light from the other night light, and assuming that each night lights is bright enough to reliably trigger the other's sensor, then you have discovered a configuration that computer engineers call a "flip-flop". https://en.wikipedia.org/wiki/Flip-flop_%28electronics%29 It has another name, "bistable multivibrator." "...


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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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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 resistance, ...


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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 ...


2

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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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 ...


2

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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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 ...


2

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 ...


2

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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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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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 ...


2

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 be ...


1

I guess the point is that at least ion-diffusion based memristors change their state depending on the total charge passed through it. Thus one can use large current to write and low current to read. Additionally one can imagine that ions move by hopping so there is a threshold voltage required to write. Employment of sub-threshold voltages will allow one ...


1

The problem here - and it is an easily missed one - is in assuming that energy is conserved in your system. Consider just a single charged capacitor with a charge q and and a capacitance C. Connect it across another capacitor which is uncharged but has the same capacitance C. The energy of the system before connecting the two capacitors together is $Q^2/(2C)$...


1

The above graph is for passing AC through an LC circuit. A large capacitor can decline in voltage very slowly, and the voltage may be further stabilized by a small amount of negative feedback.


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Say you have a capacitor connected to a voltage source ($v_s$). After the capacitor has fully charged,... If you have an ideal capacitor connected to an ideal voltage source, then there is no after. By definition, the voltage at the terminals of the voltage source is constant, ($v_s$). If the capacitor is connected across the voltage source, then the ...


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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 ...


1

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 ...


1

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 no ...



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