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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
What?
In May 28, 1946, a survey conducted by Bell Labs offered “a discussion of some proposed names”
Among them was "transconductance/transfer varistor".
So the question repeats the common mistake that it was "transfer resistor".
How does a submersible water pump work in a well?
A submersible pump is normally fitted with a float switch. As the water rises, the float switch turns the pump on. When the pump empties the water from the level and the level falls again, the float switch turns the pump off again.
FM signals travel as what changes?
FM signals travel as changes in the frequency of the wave.
ANSWER: DEFINITELY not frequency remains the same.The duty cycle changes.
It definitely IS the the frequency which changes. It changes at the same rate as the frequency of the modulation.
It can be demodulated with a frequency discriminator. If the frequency remained constant and its "duty cycle" changed, the discriminator wouldn't demodulate it.
How many valence electrons are there in doped materials of p-type and n-type materials?
1. N and P-type Semiconductors
Neither pure silicon(Si) nor germanium(Ge) are great conductors. They form a crystal
lattice by having each atom share all of its 4 valence electrons with neighbouring atoms.
The total of eight electrons can not easily be jiggled out of place by an incoming current.
If , however, the crystalline array is "doped"(mixed with an impurity) with arsenic which
has five valence electrons, the behaviour of the lattice will change. Four bonds will be
still be made but there will be a leftover electron that can wander through the crystal.
This is called an n-type semiconductor.
Boron can also be used to dope a pure crystal of silicon. But since boron only offers 3 of
the four electrons that a silicon atom needs, each silicon center is left with a hole.
Semiconductors made in this manner are called p-type.
In a p-type material if an atom from a neighbouring atom fills the hole, it will leave a
hole adjacent to it. This process will continue in a domino effect and the hole will be
moving in the direction opposite to electron-flow. In reality the atoms are remaining fixed
in the lattice, but there is an illusion that the holes are physically moving.
How is The range of an voltmeter is increased?
The easiest way is to put a high resistance in series with the meter.
You must know the input resistance of the meter. This is specified in the owner manual.
Some meters are specified as having a certain input resistance.
If a meter has a 1 Megohm input resistance, you can scale it up by a factor of ten by putting a 9 Megohm resistor in series with one of the probes.
Some meters are specified in "ohms per volt".
The Ohms/V rating can be different on different scales. If a meter is specified on the 600 volt scale as having "20,000 Ohms per Volt", then this means that the meter's resistance is 20,000 * 600, = 12,000,000 Ohms. 12 Megohms.
To expand the meter's 600V scale to 10X the rating (6,000 volts), you would put a 108 megohm resistance in series with the probe. This resistance could be made up of ten 10 Megohm resistors, a 7.5 megohm resistor, and a 470 Ohm resistor. Even though that is only 107.97 megohms, the error is less than 1%.
To expand the scale to 2X (1,200V) you would put a 12 megohm resistance in series with the probe.
High voltage low power resistor strings can be put inside plastic, glass, or ceramic pipes. Consult the appropriate industry publications for recommendations.
warning:
Be careful when measuring high voltages. Never work alone.
Most simple resistors are not rated for high voltage over 200-500 volts per each resistor and will arc or burn. Injury or death may result.
I prefer to hook the "hot" end of the probe to the high voltage test point and let it hang there, and not to hold it by hand. Then I energize the equipment and take the readings. After I am done, I discharge the high voltage and safely remove the probe from the equipment.
Poorly made or defective probes have killed people.
What are the parts in a diode?
That depends on the diode, however I will talk about a very basic one. Simple version: One side is called the anode, the other is the cathode. Current only flows from the anode to toward the cathode. It is blocked from traveling in the other direction. Less simple version: I am including this since you asked about the parts "in" a diode and not the parts "of" a diode. Diodes are semiconductor devices and are constructed with two pieces of semiconductor material (silicon, germanium, etc), one of which has been designed with extra electrons in it (cathode side) and one with extra spots for electrons to occupy (anode side) . Remember current flowing in one direction means electrons are traveling in the opposite direction. Now, if you apply enough positive voltage to the cathode, current will flow to the anode, but it will damage the diode if it is not designed to handle it. Some diodes are even designed to be used this way (look up zener diodes). To really understand the physics of what is happening in these materials, you need some knowledge of quantum mechanics (not joking) but that is beyond this question. Hope you got what you needed.
What is handshake in computer language?
A computer handshake is basically this: its a term used to describe the process of one computer establishing a connection with another computer or device. The handshake is often the steps of verifying the connection, the speed, and/or the authorization of the computer trying to connect to it. An example of handshaking is when a modem connects to another modem; the tones heard after the dialing is the handshake and can be thought of as the computers greeting each other.
Think of it as literally a handshake between two people, or two dogs in a park sniffing each others....You know. If the "Handshake is successful: BAM! protocol (computer communication language) is established and life is good.
Protocol (BTW) can be physical (USB, Cables etc) or wireless (on the internet) via packets which are.............
A Packet is a series of bits transmitted or received by a computer. Internet traffic is routed and controlled in packet-form.
What enables the electric current to move through a material?
The electric current moves in the direction opposite to the flow of electrons by convention.When a potential difference is applied to a material which has "loose" electrons, the electrons move in a direction opposite to the potential gradient and the current moves in the opposite direction to the flow of electrons.This is how current flows in materials.
How can be three phase transformers connected in parallel?
It is common to pull parallel conductors to a transformer when the expected current is high enough. It can become difficult to pull 400A and larger wire so you can use 2,3 or 4 sets of smaller parallel wires to accomplish the current.
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Transformers are frequently connected in parallel with each other in order to increase the amount of apparent power (expressed in volt amperes) they can supply to a load.
What is meant by parasitic capacitor?
Parasitic capacitance is the unwanted capacitance between:
1. A signal line and other signal line.
2. A signal line and earth.
3. A signal line and power supply line.
Not that, I remember all (even most) of the effects, let me answer you with whatever I remember:
1. Unwanted coupling between two different signals, resulting in "crosstalk" between two signals. One signal interferes with other and other interferes with one.
2. attenuation / distortion of high frequency signals which have high impedance / limited current capability.
3. Ringing (unwanted oscillations) rising edge and falling edge of the signals rectangular / square wave.
How many volts does a computer monitor use?
from the wall it could be 115v ac, or in non American countries that use it 230v ac.
internal voltages range from 12v dc, 5v dc, 3.3v dc.
Advantages of transistors over triode?
Transistors are sometimes referred to as semiconductor triodes.
OK, but to answer the question:
Vacuum-tube triodes need some hundreds of milliwatts to watts just to light the filament/heater. This is wasted power that can appear as waste heat in the circuit, and reduces the electrical efficiency of the vacuum-tube triode. Triodes also have limited lifetimes, commonly due to the filament/heater burning out, or losing its electron emission. Transistors have no such limitations and are (i) much more efficient, (ii) can run at much lower power, and (iii) have very long lifetimes.
Vaccuum-tube triodes cannot be made much smaller than around 10 mm/half an inch in diameter, and maybe the same length. Transistors can be made at the nanometre scale, so transistor electronics are much more compact. Imagine putting together a USB memory chip with (at least) 32,000,000,000 triodes!
Conventional triodes are able to operate to about 5 GHz (5000 MHz). Some special valves can work at higher frequencies, about around 100 GHz is the limit. Such valves are large, expensive, and have high noise figures. Low-noise, small, cheap transistors exist that can easily work past 100 HGz.
What is negative feedback in an amplifier?
feedback that reduces gain to help stabilize amplifier operation. gain is easy and cheap to get, stability isn't. its a tradeoff. so amplifier is deliberately designed with much more gain than needed and negative feedback sacrifices some of that gain to stabilize it.
Why don't plastics conduct electricity?
In general, plastics are composed of many chains of complex molecules. In a lot of cases, all the valence electrons of all the atoms of the material are in Fermi energy levels below the conduction band. That is, the energy required to move electrons in plastics is "high" because the energy levels that electrons would have to be in within the structure of the plastic are well above where the electrons are actually hanging out.
The conduction band is a term we apply to the energy band that electrons have to be in to support current flow. Remember that current flow is like musical chairs in that everyone has to "move over one" all along the current path for current to flow. It's isn't about one electron going "into" a circuit at one end and that same electron coming out the other end. The "willingness" of electrons to "move over" to support current flow is conductivity, and electrons that are in "too low" an energy level (because they are being "kept at home" by the chemical structure of the material - the plastic) won't help with conduction. Just as a quick contrast, in a metal, there are lots of electrons in energy levels high enough to support conduction. These are the so-called "free electrons" you hear about. Plastics don't have them.
The emitter bypass capacitor, in a typical common emitter configuration, increases gain as a function of frequency, making a high pass filter. Removing the capacitor will remove the gain component due to frequency, and the amplifier will degrade to its DC characteristics.
Are the voltages across all branches of a parallel circuit the same?
In a parallel circuit, all the branches are joined together at their start and again at their end by a conductor (usually wire).
Now, the surface of a conductor (ideally) is an equipotential surface. That is, any point of its surface has the same electric potential.
And since the voltage across each branch equals the difference in electric potentials between its start and its end, and these potentials are the same for every branch, it follows that the voltages across each branch must be equal to each other.
150 kHz
Why ohm's law is not applicable in networks?
Ohm's Law: Volage = Current times Resistance Yes, voltage is proportional to current. That applies in simple circuits as well as to complex circuits such as electrical networks. Your statement that "voltage is inversely proportional to current in electrical circuits" is incorrect. Perhaps you are not considering some critical part of the statement, or you simply heard it wrong.
How can calculate the approximat internal resistance of the multimeter?
If the meter is digital you will be told in the instrument's specifications what the internal resistance is. Most digital multimeters have an input resistance, on all voltage ranges of 10 Mohms.
The resistance of most analogue multimeters depends on the voltage range, being given as "x kohm/volt", and is called the meter's sensitivity
The better analogue multimeters have a sensitivity of 20k/volt, so, for instance, on the 30V range of such an instrument, the resistance would be 30 x 20,000 = 600k.
There are, or were, also analogue instruments which had a constant 10 Mohm resistance on all voltage ranges. The Philips PM2505 being one example.
Why should a person who handles electronic components wear a grounded wrist strap?
Correct Answer= "To reduce or eliminate static charges"
What does a digital clock crystal do?
An alarm clock works by specifying a specific time for an alarm to sound, at which time it is electrically or electronically activated. It is crucial that the clock is set to the correct time.
How do you test chopper transformer?
A chopper transformer is a kind of transformer used in an switching power supply.The primary input voltage of it is a Direct current (D.C) unlike any other ordinary step down transformer which uses an Alternating Current (A.C).Chopper transformer uses a switching transistor to produce a secondary voltage..
Electrical current is a fascinating and powerful tool. It can be both safe and deadly: the emissions from a Tesla coil, while awe inspiring, pass harmlessly around and through humans; yet, ramp up the current enough, and severe effects can occur.
The major factors that affect a person are: the amount of current, measured in amperes or "amps"; the path the current takes through the body (i.e. through the heart); and the length of time the body is exposed as a circuit.
The voltage, environmental moisture, whether the heart is in a beat or not, and the person's health can also affect the severity of the shock. The following list details effects of current. Note that 1000 milliamperes (mA) equates to 1 ampere (A).
1 mA of current causes a bit of a tingling sensation, but can be dangerous under some conditions.
5mA of current results in a slight painless shock. Strong involuntary reactions can cause injuries to the person.
6-16mA results in a painful shock, and the individual is less likely to have control over their muscles.
17-99mA results in extreme pain, respiratory arrest and strong muscular contractions. Death is quite probable at this point.
100mA-2A results in uneven, uncoordinated pumping of the heart. Nerve damage begins here. Death is highly likely.
At more than 2 amperes, the heart stops, internal organs begin to cook, and sever burns occur. Death is quite probable without immediate medical assistance.
See the related links below for further details.
Does electronics and telecommunication has more scope or electronics and instrumentation?
Electrical-Electronics: 1.Electronics came out of electricals 2.Electricals: base & Electronics: Speciality
Electronics-Instrumentation: Specialities based on Electrical Electronics i a part of physical study of electrons emission. Instrumentation is a fiels of specialty related to monitor,calibrate electronics components.
What is the differences among TTL and CMOS logic families?
{| ! CMOS ! TTL | CMOS has good packing density. TTL takes up more space CMOS has better noise immmunity. TTL has a smaller noise immunity range CMOS has a large fan out. TTL can power less inputs CMOS consume less power. TTL use more power CMOS are highly static sensitive. TTL IC's tend to be less susceptible to static electricity CMOS uses FETS (Field-Effect Transistors) TTL uses BJTs (Bipolar junction Transistors CMOS can run with a range of supply voltages. TTL IC's run with a 5V supply. CMOS uses Vdd and Vss for it's power connections TTL uses BJTs (Bipolar junction Transistors CMOS takes a lot less power and is therefore suitable for battery applications, but generally speaking can't run as fast. TTL devices can drive more power into a load. CMOS chips can be damaged by static electricity: even a static jolt that you or I can't feel might destroy a CMOS chip! |}
