Electronics Engineering

no

TIP120/TIP121/TIP122

NPN Epitaxial Darlington Transistor

• Medium Power Linear Switching Applications

• Complementary to TIP125/126/127

Negative temperature coefficient of resistance means that as the temperature of a piece of wire or a strip of semiconducting material increases, the electrical resistance of that material decreases.

Transformers are rated in KVA, both the primary and secondary windings have the same KVA rating. (KVA is the voltage multiplied by the amperage then divided by 1000).

If you have a 10 KVA step up transformer with 120V on the primary:

A = 10k / 120 = 83.33A

and if the secondary produces 240V:

A = 10k / 240 = 41.667A

This depends on the IC, and package size. If you look in the data sheet for the particular IC you are wanting information about, there will be a page dedicated to the physical size and layout of the chip.

When electrons are given energy, they can "jump" to a higher energy level or "electron shell". It would then be in an excited state. When it returns, it will emit the energy in the form of an electromagnetic wave (light).

A good example is a simple filament lightbulb. Electrons undergo thermal excitation (excited by heat) and will emit a whole range of electromagnetic waves (in the visable region of the spectrum, but also a lot of lower energy infra red light)

Thevenin's theorem is a basic equivalence principle for circuit design. It can simplify a very complex circuit to a very simple equivalent. This is done by finding the Thevenin Resistance as well as the Thevenin voltage and current. Once these are known, the equivalent circuit is simply a voltage source in series with a resistance.

Parallel. Coz all the elements will get same voltages from the sources. in case of series connection, the voltage is divided between all elements.

Voltage drop

DC current will not pass through a transformer, in the sense that a DC current on the primary will not produce a DC output from the secondary. A constant DC current will not produce any output from the secondary but there may be transient effects as the DC current is connected or disconnected (in which case, it's really an AC current, isn't it?) More about this below because I don't think that's really the question. If you pass DC current through either winding of a transformer, two things will happen. First, you will heat up the transformer and, if you have enough DC current, you will burn it out. Second, you will induce a magnetic field in the core. The more current, the closer the core gets to "saturation" or the maximum field it can support. This is important if there is both DC and AC current present because the more DC field in the core, the less core capacity is available to "transform" AC current. As the core operates closer to saturation, the AC waveform will be distorted and some of the AC power will be lost to heating the transformer. For example, if the primary of a transformer is connected to an AC source, and a DC source is connected to the secondary, then the primary current drawn by the transformer will increase, possibly enough to destroy the transformer. There are special transformers, called magnetic amplifiers, which take advantage of this effect to use a DC current to modulate an AC current. There are transient effects of DC currents in a transformer winding. As the DC current magnetizes the core, energy is stored. When the DC current is disconnected, this stored energy wants to leave the core. It can do this by inducing a voltage in either of the windings. If both windings are open circuit, this voltage can be very high. So you may see a spark jump when the DC voltage is disconnected. In a large transformer, this discharge may break down the transformer insulation and damage it. Some switching power supplies take advantage of this effect in which case the transformer is wound slightly differently and called a "coupled inductor."

Depending on the value, it varies.

Using a multimeter set for Kilohms resistance, check that it appears open circuit. This may be hard to determine, due to other components in circuit. It should NOT show zero resistance.

Electrolytic capacitors above 1 microFarad will show some storage of charge.

Using the meter with the probes one way, there should be a percepible rise of resistance. Reverve the leads and you should get an intial negative value followed by a slow rise in resistance.

If there is no perceptible rise, it could be open circuit. If it shows Zero, it will indicate a dead short.

No electricity is transmitted to Andaman from mainland.In fact it is generated at each island with the help of diesel generators according to need of the particular island.However, power is transmitted from Kalpong hydro electric project(North Andaman) to middle andamanwith transmission lines of 33 KV.

Electrons have negative charges, and unlike neutrons and protons are located on the outside of the atom. They are generally located in electron clouds around the atom, and stay there because of their attraction to protons that are in the nucleus of the atom.

The answer to this question depends on the application. Generally no - manufacturers of devices design the components precisely, and if they've used a 35uf cap, they've probably done it for a reason. In an audio application the change of a capacitor value will give you a different tonal quality compared to the 35uF cap, though this isn't always a bad thing, though I wouldn't recommend changing it unless you're sure of the effect on the signal. In a power supply application, the capacitors are used to limit something known as ripple current. In this application the higher the capacitor value the lower the ripple current, which is something that is usually a good thing. If you want a more detailed answer i'd need to know more about the circuit you are working on.

An LED is a Light Emitting Diode. It is a semiconductor device designed to produce a certain type, wavelength, etc. of light.

As opposed to an LCD which is a Liquid Crystal Display, does not emit light of any real intensity, although excitation methods have been developed for use in TV's, cellphones, etc. More common now than LED's. The major difference is that LED's have to have power all the time to emit. LCD's just need power to change. So, they are more energy efficient.

a conductor which doped interncily i.e doped externaly is semiconductor

m=1/1-(v/vbd)n

m=multipulfactors

v=applied revese voltage

vbd=break down reverse voltage

n= emperical constant

n=4 for n-type si

n=2 forp-type si

An Analog Signal is a continuous signal, just like an electric current that flows through the copper cables when your electrical appliances are turned on. This continuous signal represents physical measurements. An example of this would be with an analog audio signal, the voltage amount of the signal changes continuously with the change in sound waves. Analog Signals are normally represented as electrical signals, but there is also Classical Mechanics, Pneumatics, and Hydraulics technique's that can be used in analog signals.

there is difference between doping levels.In normal PN junction diode we add 1 impurity for 108 atoms where as in tunnel diode we add 1 impurity for 103 atoms.there is a probability that electrons may penetrate through barrier.So will not disappear

in tunnel diode we get maximum current before barrier disappear where as we get maximum current after break down(there is no barrier)

this effect lies within a certain voltage limit of 0.4V.

When we consider the energy band structure in case of PN junction diode the fermi level lies inside the forbidden energy gap.In case of tunnel diode,the fermi level lies outside the forbidden energy band.

In tunnel diode, there is a topic about negative resistance region where as we cannot discuss it in PN junction diode.

ur friend,

uma.

No. It means it has a resistance of 2,200,000 Ohms. Plus or minus the tolerance.

Fairly certain Beryllium Oxide is an extrinsic semiconductor with band gap 10.6 eV.

Otherwise the answer is Boron Nitride (6.36 eV)

Both alternating current (AC) and direct current (DC) describe the nature of the current in terms of its direction. DC describes when the flow of electric charge goes in a constant direction whereas AC describes when the flow of electric charge constantly reverses; in other words, the electrodes of the power source constantly switch between positive and negative.