0
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 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.
= =
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! |}
How do you detect an electromagnetic signal?
A radio tuned to the desired frequency would do the job.
What must be applied to an electric charge to make it flow in a circuit?
There are many complex explanations for current flow in electronics. The answer below describes the basic requirements without including great detail. For a more academic discussion, you are advised to look at relevant sections of text books on electrical and electronic engineering.
In order for electrical current to flow, there must be two things:
1) A voltage (sometimes referred to as a "potential difference"). The voltage can be created by a battery, a generator, a solar cell or a mains voltage outlet.
2) A complete circuit. This must include conductors such as wires that start at the positive terminal of the voltage source and at the far end, return to the negative terminal of the voltage source. Other components such as lamps, resistors and switches can form part of the complete circuit.
We must have a voltage for current to flow because without it, there is no "electrical force" to cause the current to flow.
We need a complete circuit so that the current can flow from the positive of the voltage source, through conductors and return to the negative of the voltage source. Current will flow through any complete circuit. If a switch is part of the circuit, when it is open, no current can flow because the circuit has been broken. When the switch is closed, the circuit is complete and current will flow once again.
Therefore, it is possible to have a voltage without a current (switch open, for example) but it is not possible to have a current without a voltage.
NB: Mains electricity is alternating current. It follows the same principles as the DC examples mentioned above although there is a changing voltage rather than a constant voltage.
What metal are paper clips made of?
its a mixture of aluminum and steel ,having more resistivity anr moreflexible .
For radio broadcasts sound signals are converted to?
For radio broadcasting, sound waves are converted to electrical waves that are further transmitted. This transformation is done by a device called a transducer, which converts physical parameters into an electrical form (signals).
In a parallel circuit is the current is shared between the loops?
The current splits, part of it goes through each of the separate branches, then it gets back together again.
This answer is misleading.
What actually happens is this. Each branch draws a current which is determined by the supply voltage divided by the resistance of that branch. The sum of these branch currents is then drawn from the supply.
So, the current doesn't actually 'split', but is the sum of the individual branch currents.
How do you block radio signals at home?
There is not one answer to this question but the most important thing to check is that the cable/antenna/satellite connector is connected properly and tight. Think of this connection as your desired signal path and the radio stuff as the undesired signal. The quality of the desired connection can make all the difference. There are so many variables to the question that you may need to repost with specifics/progress etc.
How do you test a capacitor using a multimeter?
A cheap multimeter can be used to test if a capacitor is burnt out. Connect one lead of the capacitor to one lead from a resistor (about 50k ohms). Set the multimeter to a high "ohms" setting and place the test leads on the remaining cap and resistor leads. The display should begin at 50 KOhms and then get higher and higher until it reads infinity/overload.
A bad capacitor will either start at infinity/overload or start at 50KOhms and stay there. It won't tell you the ferad rating of the capacitor, but it will give a starting point to troubleshoot.
