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Electrical Engineering
Electrical engineering is a field of engineering that deals with the study and application of electricity, electronics and electromagnetism.
23,056 Questions
How depletion region across zener diode gets thin?
A diode is basically a PN junction device. P type semiconductors are rich in holes while N types are rich in electrons. (Rich means majority carriers here, which are found in the outer shell of atoms).
Thus at the junction of this P and N type material, electrons and holes will combine resulting in a deficiency of charge carriers. This is termed the depletion region.
When you attach the negative terminal of a battery to the N end of the diode and the positive terminal to the P end, the electrons will be repelled towards the junction and holes too will move towards the junction region, making it thin (narrow) (Further increase in voltage will make current to pass through). The opposite occurs when they are connected the other way. The region becomes thin.
For normal operations, zener diodes are connected in reverse (diodes usually are connected reversely unless you want drop some voltage) the depletion layer widens, as described above. But at a certain reverse voltage, the zener starts to conduct suddenly. This is called avalanche/breakdown voltage. How the layer becomes thin (if at all, seems improbable) when they are reverse connected, I do not know.
How did increasing the stimulus voltage in the simulation affect the action potential?
Increasing the stimulus voltage in the simulation affect action potential mainly because increasing the current will automatically increase the voltage.
How are lights wired in a house?
"House wiring" is a category of wiring which refers to wiring within the confines of an immobile dwelling house, apartment, etc. It does not refer to mobile homes, caravans, canal barges or any other kinds of mobile dwelling.
Someone could spend a week typing to "tell you about house wiring". Go to a hardware store like Home Depot, buy a book on home wiring and read it!
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No, its not too hard to describe: in USA, Canada and other countries which use the same standard alternating current service - which runs at 60 cycles per second - it comes to the outlets using black and red hot wires, a white neutral wire and a bare ground wire.
Each circuit is built to provide electric power for a particular use: for lights, for small appliances - such as camera or shaver chargers, radio and tv, toaster, etc. - or for large appliances such as freezer, cooker, washer, dryer, water heater, air conditioner, etc.
The maximum current supplied in each circuit is limited to the capacity of its circuit breaker, which depends on the thickness of the wires used.
In turn, the wire thickness used to build a circuit - and the voltage it supplies - depend on the uses for which the circuit is intended. A rough guide is: the bigger and heavier the appliances are, the more voltage and current they require. In a normal size home, the sizes of its circuit breakers start at around 15 amps and go up to 100 or 200 amps for the main incoming service line wiring.
If there are three wires in a circuit - colored "black, white and bare" or "red, white and bare", that circuit is for 110 to 120 volts to be used for lights and small appliances.
If a circuit has all four wires: "red and black and white and bare", that circuit supplies 220 to 240 volts for a cooker, a washer, a dryer, a water heater, etc.
Everything that is installed as house wiring must comply with the NEC (National Electrical Code) and any further requirements of the locality. (Town, city, state, etc.) For example, in New York City the wiring codes - which are part of the city's Building Codes - do not allow new home circuits to be installed by anyone who is not a licensed electrician.
Many other places in North America allow home owners to apply for a Home Owner Permit, but any DIY work done must still comply with the requirements of the NEC. Such DIY work is often checked by the safety authorities for compliance with the NEC before they will allow it to be connected to the incoming service at the main breaker panel.
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As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.
Before you do any work yourself,
on electrical circuits, equipment or appliances,
always use a test meter to ensure the circuit is, in fact, de-energized.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
What is used to provide low voltage enrgy?
Assuming 24 volts or lower is implied in the question, low voltage energy can be taken from a battery or from a low-voltage transformer fed from the house supply.
Rotational force is usually spoken of as torque. Torque is a term we use to talk about a force that acts on a body to change its rate of rotation. It is the rotational equivalent of force in a linear motion system. A torque can arise from a single offset-applied force (using "inertial force" or "central bearing / pin force" to generate the balanced couple), from multiple applied forces, or when analyzing structures... from the slices of the structure outside the area of consideration. Roughly, it is a "force times a closest distance", even if that distance is to a point not on the structure under consideration. See the below link for formalism. In general, a torque does not produce linear displacement of the thing that is being "torqued", but nets to zero displacement over some length or some time. Technically, torque is the turning effect of a couple while moment of a force is the turning effect due to a single force but they are often interchanged. Torque is a type of force that causes an object to rotate.
Why carbon is used in brushes instead of semiconductor material in motor?
There are a number of reasons, including:
1. Carbon is self-lubricating.
2. Carbon has a negative temperature coefficient of resistance, which means that its resistance falls as its temperature increases -which is opposite that of metals such as copper.
3. Carbon is softer than copper, so will not damage the commutator.
4. Carbon will acquire the shape of the commutator segments and, so, will ensure maximum contact with them.
What is resistance of earthing electrode?
It's convenient to think of the earth electrode as being surrounded by a series of increasingly-larger 'shells' of soil, through which any earth-fault current will radiate outwards. The resistance of each 'shell' is inversely-proportional to its cross-sectional area. The shell immediately surrounding the earth electrode (1, in the following diagram) will have the smallest cross-sectional area and, therefore, the greatest resistance value; as we more further and further away from the earth electrode, each subseqent shell (2, 3, 4, etc.) increases in cross-sectional area and, therefore, reduces in resistance.
The further we move away from the earth electrode, the difference between the size of each shell becomes less and less significant and, therefore, the resistance between adjacent 'shells', will become less and less until, eventually, the increase in resistance, too, will become negligible.
The resistance of each of these 'shells' is, of course, cumulative. So, while the rate of change in resistance is greatest in the area immediately surrounding the earth electrode, the cumulative resistancecontinues to increase until it eventually become more-or-less constant. And it is this constant value that is taken as being the resistance of the earth electrode.
In practice, we cannot use an ordinary ohmmeter to measure the resistance of the earth electrode. Instead, the basis of the test is actually as follows.
A small spike is laid out in a straight line radiating away from the earth electrode. The resistance is then measured between the earth electrode and the spike, using an earth megger. The test is repeated several times, with the spike moved further and further away from the earth electrode. A graph drawn from the results shows a curve which is steepest (representing the greatest rate of change of resistance) where the test spike is closest to the earth electrode, and which eventually becomes horizontal (no further rate of change of resistance). The cumulative resistance increases, until there is no further significant increase in resistance, and this value is taken as the earth-electrode's resistance. The same results will be seen in whichever radial direction the resistance is measured, relative to the earth electrode. The area, immediately surrounding the earth electrode, in which the resistance value changes is termed its 'resistance area'.
For the UK, the wiring regulations, BS 7671:2008, specifies that the value of the earth-electrode resistance must be 'low enough to ensure that the potential of any exposed metalwork, with respect to earth, during an earth fault does not exceed 50 V for normal, dry, conditions'.
The 'On-Site Guide', a supplement to BS 7671:2008, further specifies (section 10.3.5) that the earth-electrode resistance should 'in any event, not exceed 200 Ω'.
How can you convert a 3 phase 208 volt pizza oven to 240 volt 1 phase?
Eliminate one wire from the 3 phase 208 volt and install a 240/250 volt 2 pole breaker . but the oven has to be rated for 240 volts check the nameplate on the oven or it will not work.
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Some three phase resistive load devices will allow the device to be used on single phase. The wiring diagrams will be on the nameplate of the device. It usually involves the repositioning of jumpers to create new connections within the device to keep the resistive coil currents equal. This is to provide equal heating throughout the oven. Other wise there would be cool spots where the third phase leg resistive coils had been taken out of the circuit.
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As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.
Before you do any work yourself,
on electrical circuits, equipment or appliances,
always use a test meter to ensure the circuit is, in fact, de-energized.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS
What is common to both thevenin and norton theorem?
To solve any D.C. circuit by using Thevenin Theorem,
First of all load resistance RL is disconnected from the circuit and open circuit voltage across the circuit is calculated (known as Thevenin equivalent voltage)
Secondly, the battery is removed by leaving behind its internal resistance. Now we calculate equivqlent resistance of the circuit ( called Thevenin equivalent resistance).
Now we connect Thevenin Voltage in series with Equivalent resistance of the circuit and now connect load resistance across this circuit to calculate current flowing through the load resistance.
Whereas in the case of using Norton theorem, we again remove the load resistance if any, and then short circuit these open terminals and calculate short circuit current Isc.
Second step is same as in Thevenin theorem i.e. remove all sources of emf by replacing their internal resistances and calculate equivqalent resistance of the circuit.
Lastly, join short circuit current source in parallel with equivalent resistance of the circuit. Now, we can calculate votage across the resistance which was connected in parallel with Isc.
So, by knowing the open circuit voltage, we can calculate current flowing the resistance and on the other hand , by knowing the short curcuit current , we can calculate voltage across the resistance.
Split load refers to a type of electrical distribution system where the load is divided between two or more circuits or sources, typically to optimize performance and reliability. This approach can help balance the electrical load across different phases or components, reducing the risk of overload and improving efficiency. In some contexts, split load may also refer to a distribution of tasks or resources in project management or computing.
What is the differences between cyclo converter and matrix converter?
u refer cycloconverter and matrix converter
How does the power factors affect an electrical system?
Power factor is the real power (watts) divided by apparent power (the vector sum of real and reactive power). Reactive elements (things that have inductance or capacitance) cause phase shifts between voltage applied to them and current passing through them. This phase shift is a result of these elements holding power, then releasing it. Since these elements are not actually using power, this does not show up on your electric bill (unless you are billed on VARs as well as watts). Although they don't use real power, these reactive elements do cause "extra" current to flow, which the power company must supply. If this current is excessive (so you have a very low power factor) the power company must install oversized equipment to meet your demand; this means an added expense for them, with no payback on your electric bill. This is why power companies will often require a certain power factor be met, or bill you extra per kWh of use.
Note power factor is a result of the load, not the other way around (a better question might be what is the a load's effect on power factor).
Which is best core or shell transformers?
Because the flux leakage is less in shell type than that in core type T/F.
Additional AnswerA shell-type core's magnetic circuit is equivalent to a parallel electric circuit, so it has a lower reluctance compared to a core-type core of similar cross-sectional area.
What is meant by unilateral and bilateral circuits?
if a network is having both sides voltage and current sources; and if the direction is changed from any side there will be no change in circuit characteristics. so it is called bilateral network.
What happens if you short the shunt windings of a motor?
Answer:
If the shunt winding is open the motor won't start, but if the shunt open while the motor is running, the motor will keep on running as if nothing went wrong, except if the wire of the winding get maniacally between the stator and the fields the motor can be damaged beyond repair. But normally the shunt windings is done with very thick conductors, so the chance that the shunt will go open is zero.
How much volts or currents in order to produce one tesla?
There is no straightforward answer to your question. A tesla is the unit of measurement for magnetic flux density, defined in terms of magnetic flux per unit area. Magnetic flux density is determined by the magnetic field strength of the magnetic circuit in question which is expressed in ampere (turns) per metre. Unfortunately, the relationship between magnetic field strength and flux density isn't straightforward, as it depends on the shape of the B/H curve for the magnetic circuit's material. So, as you can see, there are too many unknown variables to give you a straightforward answer.
Can 10-3 wire be used for an electric oven?
10 Guage Wire Will Handle 30 Amps. Most ovens require 50A, so no.
In electrical engineering what is a spur circuit?
spur evolves from spurious terminology.In electrical terminology it is denoted by a range of frequency through which any electrical circuit (specaially in case of RF and microwave circuits) is operated.
Are bulbs connected in series dimmer than one on its own?
No, lights in a simple circuit are not dimmer than in a series circuit. This is because there is only one bulb in a simple circuit and that bulb can have the full power of the battery, while in a series circuit, the power is shared between two or more bulbs.
If the devices are in series, then the current from the generator is (40/16) = 2.5 Amp.
If the devices are in parallel, then the current from the generator is (40/3) = (13 and 1/3) Amp.
Who discovered the generator effect and when?
No-one 'invented' the generator as we know it, today, it simply evolved from various experiments conducted in the 19th century by scientists, such as Michael Faraday, using devices that we would not really recognise as generators these days.
What is the purpose of dc power?
theperpose of a power supply is to step up or step down an ac voltage to a desired dc value
What is the consequences of electricity supply system failure?
Current always follow path of least resistance.Occurrence of fault means current find unintentional low resistance path to return back to source . This resistance is so low, that it draw abnormally high current from source. This may cause damage to the conductor if it is not rated to deliver that high current. Also it may cause damage to source if it is not rated to deliver that current. Also, as the current suddenly increase, voltage drop increase and power system voltage dips.
Why must do the insulation testing in circuit?
Insulation resistance testing involves applying a voltage across a dielectric, and measuring the resulting current and resistance. However, in order to get a proper reading, any electrical charge still within the system needs to be taken out, so as not to mess with the readings.
