Electronics Engineering

Digital communications has a lot of scope in our life . For example, all the cellular networks,internet and other advanced communication systems are based on digital technology. So, there are a lot of companies growing in this sector.Today, fast and cheap communication has become the demand of public and thus there is a huge competition between companies to sustain in the market.

When NPN transistors are used in the most common amplifier configurations, they require a power supply with positive polarity with respect to common terminal. PNP transistors instead require a negative power supply. Over many years the positive power supply has become a design standard. This means that, for "Common Emitter" and "Common Collector" amplifiers, NPN transistors must be used. The same was once true for logic circuits: for positive power supplies, the logic gates would be built from N-channel FETs. But since the 1980s an improved setup has been used: CMOS logic which is built from approximately equal numbers of P-channel and N-channel transistors.

npn is mostly used because in npn electron current is greater the hole current.whereas in pnp hole current is greater than electron current. it is a people choise and basicaly and a manufacture choice. nobody wants to be negative. logic chips were developed for positive potential that doesn't mean that these chips cannot be used at a negative potential quite the contrary as long as the chip sees a positive voltage across them they work. you may develop a computer whereb\y the logic is gnd as positive and -5v as -vss. so you see it is a human choice.

The FET is a semiconductor device with the output current controlled by an electric field. Since the current is carried predominantly by one type of carriers, the FET is known as a unipolar transistor.

In most countries of Europe, South America, Africa and Asia, they use 220 VAC, usually at 50 Hz.

The voltage issue is solved by transformer of a voltage converter.

Transformers must be used with electronic devices (cameras, DVD players, answering machines, etc.) . A transformer will reduce the voltage from 220 VAC to 110 VAC, which is what the US equipment use.

Voltage converters can ONLY be used with hair dryers, hair straighteners, most small appliances (mixer, can opener, drills, etc.) Voltage converters provide 220 VAC to the appliance. However, because the converter only conducts current a fraction of each cycle, the power applied to the appliance is reduced by 50%.

Transformers are quite heavy and are marked with a "VA" (volt-ampere) figure, which is roughly the power withdrawn by the equipment. In addition, they usually exhibit a body made of iron laminations, easy to spot.

Voltage converters are very light and have holes for ventilation in their aluminum body. In addition, the power they can handle isualy indicated in watts (W).

Again, NEVER connect an electronic equipment to a voltage converter. Use a transformer instead.

Better yet, travel with electronic equipment and appliances with dual voltage settings. Even better if they detect the voltage automatically, like most laptop power supplies.

If rated voltage is applied to Transformer during S/C test, The secondary winding will burn out due ta heavy current flow through the winding. During S/C test the secondary winding is short circuited so the impedance between phase and neutral is very low(only winding resistance). But the voltage across the secondary winding is rated hence heavy current flows through the winding, as I=V/Z.

it depends which rated voltage is applied. if you are talking about primary winding voltage, transformer should withstand the primary rated voltage it's been designed for (OR it has been poorly designed). Otherwise, if rated voltage is the insulation voltage between a winding and earth OR winding-to-winding, you just have to check if: 1 - it is higher than the maximum primary winding voltage the transformer can withstand (could be, could not be..). Then, you can guess if your transformer is likely to burn or not. 2 - your test setup (usually a HV generator connected between primary and secondary winding) can deliver the requested current for the setup. I guess this won't be the case, since HV testers are usually designed to generate high voltages, but very small output currents.

You can just Google the IC number and check the datasheet. This is very useful for getting the pin configuration of other IC as well.

Anyway 7486 is a 14pins, 4 independence gates of XOR

Gate Input Output

#1 Pin1 Pin2 PIN3

#2 Pin4 Pin5 PIN6

#3 Pin10Pin9 Pin8

#4 Pin13Pin12 Pin11

Others

Vcc Pin 14

Gnd Pin 7

Hope that helps.

Ulitization factor is how much of the designed total is used. My house is fed off a 50KVA transformer. It's capable of supplying 50KVA continuously, but it's probably only gets used at its' full potential every once in awhile (when my neighbors and I wake up in the morning, and when we get home from work and eat dinner, perhaps). Say it only gets used at 30KVA on average. The utilization factor would be 30/50, or 60%.

Assuming that the rectifier will be followed by a filter capacitor, the p.i.v. should be at least twice the peak of the applied a.c.

(The capacitor will charge to the peak of the applied a.c. On the next half cycle of the input, the peak of that cycle will be of the opposite sign to that of the stored voltage on the capacitor, so the two add - giving twice the peak.)

All* materials conduct electricity. The question is exactly how much do they conduct. Materials such as metals, semiconductors, graphites, etc tend to conduct electricity better than others like plastic, paper, wood, etc due to loose valence electrons that allow electric current to flow through them. Good conductors will have a low electrical resistivity. The resistivity of some common resources are shown:

Gold: 22 n Ω·m

Copper: 17 n Ω·m

Aluminium: 28 n Ω·m

Silicon: 1000 Ω·m

Quartz: 10^16 Ω·m

Rubber: 10^13 Ω·m

Note *: In 2008 scientists discovered a property called a superinsulation that in some materials at a very low temperature exhibit infinitely high resistance. Superinsulation is essentially the exact opposite of superconduction. It's mechanism is not very well understood and is an active area of research in condensed matter physics.

DC generator is used to produce direct current. The basic DC generator have four basic parts

1. A magnetic field

2. A single conductor or loop

3. A commutator

4. Brushes

The primary disadvantages of flip flop is their reacting time between the input signal and resultant Output if the signal changes between this reaction time the flip flop is unable to identify....... another disadvantage is that their is a Race between the flip flops when connected togather to change their stages

why it is necessary to decrease the pressure in the discharge tubbe to get cathode rays

An electric circuit is a closed loop that allows a flow of electrons to begin from a source of the electrons and return to the same source.

Some of the energy carried by the current from the source may or may not be released to perform useful work.

Because of the resistance of the materials in the circuit, some of the energy carried by the current is always lost as heat emitted from the circuit into the surrounding environment.

The flow of electrons around the closed loop is called an electric current.

The source of the electrons must be a chemical battery or a mechanical generator which produces a potential difference, also known as a voltage.

You'l need 5 4 to 1 muxes for making a 16 to 1 mux if your inputs are say W(0)-W(15) i.e 16 inputs ..... you start of with giving 4 inputs each to the 4 to 1 muxes the select lines for all 4 4 to 1 muxes will be common now each of the four 4 to 1 muxes is giving you one o/p so ..... take each of those 4 outputs and give them to the fifth 4 to 1 mux and voila you have a final o/p corresponding to 16 inputs !!! THIS IS HOW IT WILL LOOK LIKE inputs outputs mux 1 : w(0)w(1)w(2)w(3) m(1) mux2 : w(4)w(5)w(6)w(7) m(2) mux3 : w(8)w(9)w(10)w(11) m(3) mux4 : w(12)w(13)w(14)w(15) m(4) taking the above 4 outputs and giving them 2 mux5 mux5 : m(1)m(2)m(3)m(4) m(5) m(5) is the final output corresponding to 16 inputs W(0)-W(15)

1.having low noise as compare to analog. 2.using TDMA Iinstead of FDMA techniques used in analog. 3.in digital signals regenrative repeaters are used at every regeneration point of the signals so low loss of signals are there as compare to analog signals

The main advantage of an IC 555 is that is useful for creating different kinds of purposes like time delays, oscillator purposes, and pulse generation. The time increments are incredibly adjustable, such as from microseconds to hours.

The primary difference between a series and a parallel circuit is how many pathways the current has to travel in. Let's look at both of them and see what's up. In a simple series circuit, there is only one path for current. The current must flow through every component in the circuit.

cause MOSFET are mainly the comes into category of Semiconductors,

main work of inverter is to switch the contacts within microseconds,

here i want to give some constructional things so it could go easy to understand the things,

1] MOSFET has a three satates,

i]Deplition

ii]enhancement

iii]pick

When the current go through the system the work of 'mft' has start as a implementing the depletion region(increasing the electrons in emitter collector junction) as and as the supply gets interrupted the MOSFET comes into work within our thinking due to high electrons consumption it goes extream fast switch the signal from one state to anther,

actually MOSFET needs cery deep explination to understand it.

but the main purpose is to stop reverse impulses and quike switching from one state to another.

I don't believe 'bus' is an acronym, it's the word in it's original meaning, that of an object that moves things. A school bus moves people. In computers, a serial bus moves information in a series (one wire) while a parallel bus has many pins to move more information at a time. When the computers were new, they needed a term for moving information.

The 8085 is called an 8 bit microprocessor because the accumulator is 8 bits in size. This means that the primary data size is 8 bits. This is true even though the address bus, certain registers, and certain register operations are 16 bits in size.

A servomechanism amplifies the effort of the operator by the use of fluid pumps,electric motors,air pumps etc. Generally it can't be achieved without an external power source.

An example is power assisted steering in a vehicle. The driver moves the steering wheel and this detected by a sensor which moves the wheels via a powered gearing until the output movement is matched by the input movement. There is also a feedback mechanism from output to input which gives the driver the 'feel' that is needed to stop over reaction.

A:from a single ended none main concern is offset voltages and current offset and for some latch-up

Further explanation:

A differential amplifier is actually a very advanced (and good!) amplifier - it (at a minimum) consists of two transistors and biasing schemes, and in a basic form has two inputs and two outputs - one output is inverting, the other is non inverting, thus the two outputs can be used together to provide a 3dB (2 x) gain over using a single output.

From a signal to noise ratio, a differential amplifier is also a cut above if implemented correctly and designed well. For the best results, a positive and negative signal should be transmitted to the amplifier. One goes to either input of the amplifier, with the other to the other input. Noise inherently will be added onto both of these lines, but the noise will tend to be in the same direction for both. A differential amplifier has a high "common mode rejection", which means if the same voltage is applied to both inputs, the output will not change (it only amplifies the difference between the inputs). This is why sound boards and a lot of other A/V equipment use differential amplifiers.

If these features are not important for your design, then the added complexity of circuitry (usually requiring a positive and negative voltage, multiple transistors, etc.) becomes a disadvantage. Also, if you are just starting out, designing one well may be a bit over your head (a clear disadvantage when you don't know what's going on in the circuit - it becomes very difficult to trouble shoot).