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Electronics Engineering
Electronics Engineering is a branch of engineering that deals with practical applications of electronic components, devices, systems, or equipment. Electronics are devices that operate on low voltage sources, as in electron tubes, transistors, integrated circuits, and printed circuit boards and use electricity as part of its driving force.
24,372 Questions
resistance is useful when a plane is flying in the air, air resistance. it is also useful when a boat is floating on water, water resistance.
a close approximation of the forward current is an exponential function of voltage, but it has constants that must be empirically adjusted for accuracy. the reverse breakdown is a bit tricker to model accurately.
The function look something like this: I = K1 eK2(V-K3)
When measuring voltage drop across a switch what is the maximum allowable voltage drop?
The voltage drop should be as close to zero as would be readable by a typical volt meter. If it is measurable you likely have a problem with corrosion or oxidation in switch that is increasing resistance. If you can measure a voltage drop across a closed switch contact, replace the switch.
Or the switch is open, try flipping the switch!
What is effect of noise on digital communication system?
it will affect the output of a receiver only if it falls within the passband.in that case,the carrier and noise voltage will mix and the difference frequency,if audible,will interfere with the reception of the wanted signal..
Why you use capacitor with voltage regulator ic 7805?
in ic 7805 their is two capacitor is used one of them is used for the settling/transient time and another is used to provide inductive effect....
What would happen if the resistance in a circuit remained the same and the voltage decreased?
A well designed circuit should be able to operate over a range of voltages, not just at one voltage. Especially a circuit which is intended to be powered by a battery. As the battery starts to get used up, and the voltage drops, you want the circuit to operate as planned.
How do you check if your ohm meters resistance is working properly?
Get some resistors of known values and check your meter with them.
Does a capacitor charge fast or discharge fast?
A capacitor typically charges quickly when connected to a voltage source, especially if the resistance in the circuit is low. Conversely, it discharges relatively quickly as well, depending on the resistance in the discharge path. The time it takes to charge or discharge is characterized by the time constant (τ = RC), where R is the resistance and C is the capacitance. Generally, capacitors can charge and discharge rapidly, but the specific rates depend on the circuit components involved.
Is voltage established through a resistor or across a resistor?
Current = charge (electrons) flowing through a resistor.
Voltage = energy lost across a resistor.
Power = energy lost across a resistor per second.
So yes you are correct. Current is established through a component, while voltage and power are established across a component.
Answer
'Voltage' is a synonym for 'potential difference'. As the name implies, voltage describes the difference in potential between (or 'across') two different points. So voltage is applied ACROSS a resistor.
Further to the original answer. voltage is NOT equivalent to 'the energy lost across a resistor', and power is NOT 'established across a resistor' (power is simply a 'rate', nothing more)!
Difference between conduction current and displacement current?
Conduction refers to electrons or, "holes" in the case of semiconductors, which are conducted, under the influence of an electric field, from one place to another. However, in semiconductor there is a phenomenon called "drift current" which is more a function of very small field and random motion from one place, within the material, to another place. But neither of these is ever referred to as a "convection" current. The term "convection" is used in connection with air currents moved by differences in temperature between one place and another. Hot air tends to rise while cold air tends to fall. Consequently, a circulation of air, due to temperature is called a convection current.
What is the relation with charge on electrons to electron flow in a circuit?
Not entirely sure what the point of the question is, but here are two of the relations between the charge of the electron and electron flow in a circuit; I hope this helps.
1. The electron has a negative charge. This is an accident of history; there's really nothing fundamentally "negative" about the electron charge, it's just that some some particles have one kind of charge and others have an opposite one, and the the sign of the charge was assigned before electrons had really been discovered. The choice was arbitrary and could have gone either way, but electrons just happened to end up negative. You can blame Ben Franklin for it. But I digress.
Electric current is defined as flowing from positive to negative. If the mobile charge carriers are positively charged, then they are flowing in the same direction as the current. But if the mobile charge carriers are negative - like electrons, which are the carriers in metals - then the carriers are flowing in the opposite direction from the current. In other words, the electrons flow "backwards" because they are negative, because Ben Franklin just happened to write '+' and '-' in the "wrong" places (though he couldn't possibly have known.)
2. The electron charge is -1.6×10-19 Coulombs. To put that another way, one Coulomb is about 6.24×1018 electrons worth of charge. Since one Ampere is the flow of one Coulomb of charge per second, it is also a flow rate of 6.24×1018 electrons per second. That's more than six billion billion electrons each second for each Ampere!
Can a series circuit have more than one cell?
You can have any amount, it's the same as a parallel circuit! x
The energy carried by an electromagnetic wave is called?
EMP or electromagnetic pulse. It can disrupt electronic systems, and signals.
How do you solve color fading of television?
"Fixing" the color of TV is a bit vague. What's wrong with the color? There are some things that can be done, and some that can't. If the color is "off" and things are wack, there could be a handful of things that might contribute to the set's performance. Let's look at some. The (color) picture tube (the cathode ray tube, or CRT) has three electron guns in the back. They're all sealed inside the tube, and they stay there for the life of that tube. The cathode of the gun "wears out" after a while and it cannot support demands for "electron production" and high beam current. The cathodes of the guns are the same, but they can age a bit differently, and the supporting electronics may need to be adjusted to restore what is called the color balance. Certainly the beams should be adjusted so they run pretty much equally. But there are limits to how far up one can turn the "drives" without the color in the picture "bleeding" outside the edges of images. If the emission of one of the guns is "too low" and it can't be driven hard enough to create the nice, bright picture one wants, it might be possible to "restore" the cathode. In this process, a technician with what is called a CRT rejuvenator can "overdrive" the cathodes a bit in an attempt to get a bit more life out of the cathode, and, thereby, the CRT. But most shops don't like to do this because the process can damage the CRT and make it unusable. Plus, it may not work. It's not cost effective for them to burn time on this, even if they have the piece of gear it takes to perform the task. Let's look at some other stuff. It may be that the set has lost some of its convergence. What that means is that the beams aren't all "tracking" the same pixels at the same time. Convergence is something that a technician adjusts by connecting a piece of equipment (a "pattern generator") to the set that generates several different test pictures that can be used to line things up. The convergence magnets are tweaked to make things right. (In a few sets, the technician might have to actually go a bit farther to try to get the convergence back.) By the way, anyone who starts adjusting the convergence magnets without the equipment or the knowledge to competently set the CRT up usually makes things worse and can't get them back to the place where the adjustments were begun. A combination of these factors (and perhaps one or two other things) may be behind the need to "fix the color" of a TV. In this day and age, the set is probably at the end of its life. CRT's can be rebuilt, but almost no one does it any more. It's not cost effective to do that like is used to be. And it's not cost effective to buy a new CRT, either. New sets are dirt cheap. And that's the CRT TV's. How about a new flat screen? Or a good used set from a TV shop or thrift store? They're available to those on a budget. If you're stuck with a TV that isn't performing well and you're on a budget, start looking at the thrift stores, and the second hand stores. Check with some TV shops to see if they have some unclaimed repairs they're selling. If you're flush, treat yourself to a new set. Make it a fun adventure. Hang out in the stores for a bit and get an education. (Do not buy the first thing you see or are shown.) And donate your old set to a non-profit. Please don't toss it in the dumpster. The land fills don't need the extra junk. Good luck resolving your difficulties.
Why do transistors sometimes need heatsinks?
These types of transistors are power transistors and generate heat. The heat sink is used to dissipate the heat. If the transistor gets too hot it will fail.
a battery
What is leakage current in semiconductor?
In low voltage and electronics Leakage Current is any current that flows when the ideal current is zero.
In medium and high voltage applications it is the current that flows either through the body or over the surface of an insulator. Leakage current often arises when outdoor insulation is submitted to conductive fog (sea mist/spray, industrial smogs) or when a pollution layer containing soluble salts is formed on the insulator surface and then wetted, for example by dew or mist. These currents can reach several hundred mA and may lead to flashover of the insulation.
Can you series two 4 ohms speakers?
Yes, you can run a pair of 16 ohm speakers in series. The resultant impedance would be approximately 32 ohms. Assuming constant voltage, this would result in one quarter the original power to both speakers, or one eighth the original power to each speaker.
What are four characteristics of parallel circuit?
an example would be thus. if you had say 2 1.5 volt batteries each say .006 amps. When these batteries are in series the positive end of one is in contact with negative end of the other, pretty much like a common flashlight, and the voltage would be 3 volts., .006 amps. When the same two batteries are connected negative to negative and positive to positive the voltage would still be 1.5 volts but the amperage would be .012 amps. (amps doubled when in parallel, voltage doubled when in series)
How does an aircraft atcually get off the ground?
Simply more air pressure under the wing than over it.
If you look at an aeroplane wing it has a flat underside and then a curved top. Imagine two bits of air, both are going at the same speed when they get to the wing one has to go over the top to get to the other side (the long way) the other goes underneath (the direct way). This means that more bits of air can go under the wing in any given time than over the top. The fact that more air can then go under increases the pressure under the wing so that the whole plane is experiencing a higher pressure underneath and takes off. This is known as the aerofoil effect.
In magnetism:
An eddy current is induced into a metal when magnetic lines of force move across it. A South pole causes circulating current in clockwise direction while a North pole causes current in counter-clockwise direction. These eddy currents thus buck the applied forces. Eddy currents are undesirable when induced into transformer cores causing power loss. Lamination of core material reduces current flow in the core. Current induced into the secondary winding of a transformer is a used to step-up or step-down voltages so that they can be of a correct size for end-use applications.
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When time-varying magnetic field is applied to electrical machines like transformers, a time-varying emf is induced in the transformer cores. A short circuit occurs at the molecular level in the core. Due to less resistance, a large current begins to flow in the core. This causes heating in the core. Actually the path of the current is circular resembling the circular waves in a pool of water (eddy). Hence these currents are called eddy currents.
In fluids:
In water flow, an eddy is a current that flows opposite the normal flow. If on a river, an eddy is a current that will flow upstream in a side channel filling it, even if the flow is in an opposite direction of the original flow. It is equivalent to a stream's water level rising because the river it feeds has more water in it than the stream, thus making the water flow upstream. It can also be an area that seems not to have a current at all.
A:
Just like there exists a magnetic path due to current (charge) flow in a conductor (direction given by right hand rule), the thing works other way as well...
When there is a flux path crossing a current conducting material, there exists current paths around the flux line on the conductor plane centered to the point where flux line meets the plane. These currents are eddy currents.
Commonly available in magnetic circuits. Laminations are done to minimize the ability to flow eddy currents.
