Electronics Engineering

arrows are shown for conventional current, not electron current.

When considering standard household electricity, it will likely be a 120V circuit. Ohm's law says current equal voltage divided by resistance (I = V/R). Watts are a unit of power and are I * V.

Assuming a standard lightbulbs of the same general type, higher wattage / hr indicates a greater brightness. With Voltage held constant in this power equation at V=120V, this indicates higher currents will produce a brighter light. Going back to Ohm's law, this is achieved by reducing the resistance.

A polarized capacitor will only allow a voltage drop in one direction, due to the design of the electrolyte. The plus terminal needs to be always more positive than the minus terminal. Any other connection will destroy the capacitor.

Older style can-type capacitors have the case being the common minus terminal. Some terminals are marked only with a red dot. That is the plus terminal. Some are marked with an arrow; in general, that is the minus terminal, but you should read the markings carefully and, if necessary, consult the product specification sheet.

because at resonance frequency in LRC parallel circuit,impedance is high, so it minimize the current. thus we say its a rejector circuit .

A blast furnace is used to extract iron from its ore.

"'Zener diode' and 'avalanche diode' are terms often used interchangeably, with the former much more common. Both refer to breakdown of a diode under reverse bias. Specifically, when a diode is reverse biased, very little current flows, and the diode is to a first order approximation an open circuit. As the reverse voltage is increased, though, a point is reached where there is a dramatic increase in current. Equivalently, there is a dramatic reduction in the dynamic resistance (slope of the V-I curve) that can be as low as 1- 2 W in this region.ÝThis voltage is called the reverse breakdown voltage and it is fairly independent of the reverse current flowing.ÝThis property makes it ideal as a voltage reference.Ý "Avalanche breakdown is caused by impact ionization of electron-hole pairs.ÝWhile very little current flows under reverse bias conditions, some current does flow.ÝThe electric field in the depletion region of a diode can be very high. Electron/holes that enter the depletion region undergo a tremendous acceleration.Ý As these accelerated carriers collide with the atoms they can knock electrons from their bonds, creating additional electron/hole pairs and thus additional current.ÝAs these secondary carriers are swept into the depletion region, they too are accelerated and the process repeats itself.ÝThis is akin to an avalanche where a small disturbance causes a whole mountainside of snow to come crashing down.Ý The efficiency of the avalanche effect is characterized by a so-called multiplication factor M that depends on the reverse voltage (Equation 1). Equation 1: Multiplication Factor "Here n is in the range 2 - 6, V is the applied (reverse) voltage, and Vbr is the breakdown voltage.ÝThis is an empirical relationship, as are many of the relationships used to describe both Zener and avalanche breakdown.Ý "Avalanche breakdown occurs in lightly-doped pn-junctions where the depletion region is comparatively long.ÝThe doping density controls the breakdown voltage.ÝThe temperature coefficient of the avalanche mechanism is positive.ÝThat is, as the temperature increases, so does the reverse breakdown voltage.ÝThe magnitude of the temperature coefficient also increases with increasing breakdown voltage. For example, the temperature coefficient of a 8.2 V diode is in the range 3 - 6 mV/K while the temperature coefficient of an 18 V diode is in the range ofÝ 12 - 18 mV/K. "Zener breakdown occurs in heavily doped pn-junctions.ÝThe heavy doping makes the depletion layer extremely thin. So thin, in fact,Ýcarriers canít accelerate enough to cause impact ionization.ÝWith the depletion layer so thin, however, quantum mechanical tunnelingÝ through the layer occurs causing current to flow.ÝThe temperature coefficient of the Zener mechanism is negativeóthe breakdown voltage for a particular diode decreases with increasing temperature.ÝHowever, the temperature coefficient is essentially independent of the rated breakdown voltage, and on the order ofÝ -3 mV/K. "In a 'Zener' diode either or both breakdown mechanisms may be present. At low doping levels and higher voltages the avalanche mechanism dominates while at heavy doping levels and lower voltages the Zener mechanism dominates.ÝAt a certain doping level and around 6 V for Si, both mechanism are present with temperature coefficients that just cancel. It is possible to make Zener diodes with quite small temperature coefficients.Ý "Neither Zener nor avalanche breakdown are inherently destructive in that the crystal lattice is damaged.ÝHowever, the heat generated by the large current flowing can cause damage, so either the current must be limited and/or adequate heat sinking must be supplied."

The sine wave represents 360 degrees or a full circle. As the satellite revolves 360 degrees around the earth in its orbit this is how it is represented on a flat surface.

ohms is the SI unit of resistance MHO (siemens) is the SI unit of reciprocal of resistance ie conductance

you ask professor smith from the UNH ECE department

An encoder refers to a device that is used to change a signal or data into a code. Whereas a Multiplexer or mux is a device which performs multiplexing or it takes information from more than one channels and outputs into a single channel. Thus a multiplexer is basically a kind of encoder where its function is to combine multiple inputs into one output.

Electric current, magnetic field intensity, length of the conductor, angle between the electric current and magnetic field

ITT Tech isn't typically respected in the serious software shops. You might be able to get a job as a support engineer at a small company that just needs someone around. For a serious job at one of the big players you'll need a degree from an accredited college. We turned away quite a few people from the "matchbook school of programming", especially since we typically didn't even take a second look at anyone less than either a Masters or significant experience in the field from other companies. There are quite a few graduates from ITT Tech who are still flipping burgers. Quite a few companies need their own in-house network administrator. That might be a good place to go if you insist on attending ITT Tech.

Broadcast media AND OTHER RF COMMUNICATION use electromagnetic waves to send information across distance. An AM radio can use a very narrow frequency to send the information, but FM communications, such as television, your FM radio receiver and most digital signals, use what is called "frequency modulation" to send a signal. In a frequency modulated signal, the base sigal will start at a single frequency. To send information, the signal changes (modulates) the frequency up and/or down from that base frequency. The FCC and other regulating agencies have reserved certain frequencies for specific commercial broadcast use only. A radio signal may not "overlap" or attempt to use the frequency or any part of the frequency that has been assigned to another commercial broadcaster.

The dielectric is composed of "molecules" that are actually perfectly conducting spheres. These have radius R and are in a cubic array with spacing much greater than the radius R. With the application of a voltage, the spheres acquire the positive and negative surface charges on their northern and southern poles required to make their surfaces equipotentials. In so far as the field outside the spheres is concerned, the system is modeled as an array of dipoles, each induced by the applied field.

For fault conditions, the DC offset is caused by where the fault occurs on the voltage waveform.

When the fault initially occurs, the voltage can be looked at as an AC waveform superimposed onto an impulse response (A DC wave). The magnitude of the impulse is equivalent to the voltage when the fault initiated (flash over usually occurs near a voltage peak, providing a potentially large DC component).

The inductance of the system (j*w*L) appears as 0 impedance to this DC voltage.

Z (impedance) = R (resistance) + X (inductance), usually X >> R, X = j*w*L

Since X = 0 for the impulse, there is an initial large current since V = I / Z, and Z = R initially.

This current slowly dies off based on the time constant of the circuit, 1/(L*R).

A lot of times you will hear talk of the the DC component being caused by the "X/R ratio". The higher this ratio, the larger the DC component (generally) and the longer the time constant generally is (although this is not always the case).

Similar analysis applies to other causes of DC offset.

In general, a sequential circuit is a circuit that depends on a previous state. That means it needs to have some sort of "memory". As the name may suggest, sequence detectors are a good example of a sequential circuit. As bits (1's and 0's) are inputted, it can determine if a certain sequence has been detected. So as each bit gets inputted, it will need to remember it as it gets the next bit. You would need various IC's to create a sequential circuit; most importantly, a memory element of some sort, like a flip-flop.

One statvolt is about 299.8 volts.

No. An LED (light emitting diode) allows current to flow in one direction, thus it cannot alternate as is implied by "an AC source".

ANSWER: YES they can. Any diode can work with AC They can work from AC line directly. My overhead light in my kitchen are across 120 AC now for 8 years. But then again I know what I am doing

As Dave says there is no obvious reason to do so.

However if you put a 200mA fuse or circuit breaker in series between the supply and the load you will protect the load from pulling more than 200mA from the supply should the load malfunction. That way the load is protected from damaging itself (if that was your concern).

current is the flow of charge.

They Are Dim Because the d-cell being used does not produce enough energy to light them both