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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
Why common emitter amplifier gives phase reversal?
A: Because it is a voltage amplifier the current will inversely reflect the voltage across a resistor
Is torque directly proportional to applied voltage?
Current is directly proportional to applied voltage. Ohm's law.
Why Cable gets heated when current flows more than its rated current why?
Because if the rated current is lower than the actual current, it causes resistance to the electrical flow which in turn is dispelled as heat.
What is an electrical Britannia Splice?
The Britannia Splice is a connection between large solid wires. Several inches of each wire's insulation is removed and a ninety degree bend is made about a half inch from each end. The two wires are laid next to each other, with the bent ends separated by several inches. Another smaller wire, the wrapping wire, is wound around the assembly, starting from the center, in such a fashion that some turns go past the bent ends, after the point where the wrapping wire is wrapped on only one wire. The bent ends are then trimmed close.
While not as popular as the Long Tie Western Union joint, if properly made and soldered, the Britannia Splice is a very good splice.
What is the difference between electrolytic capacitors and normal capacitors?
because normal capacitors does not have any polaririties.
What are the properties of inductive load?
inductive load does not allow the current to become zero eve though the supply source get removed . inductive load reduce the power factor . they does not allow sudden change in current in the load ...
Inductive reactance has a unit in?
Ohms, resistance in an inductor increases as the frequency of the AC signal increases, this "artificial resistance" is called impedence, and it is measured in ohms
Can essential circuit combine in one conduit with normal circuit?
The use of the words "essential circuit" implies that you are refering to the requirements of the NFPA electrical standard, aka NEC, which is commonly enacted as law in many USA jurisdictions (but not everywhere).
The 2005 NEC discusses "essential circuits" as part of the Health Care Facilities, chapter #517
The "essential" system is subdivided into 2 subsystems:
EMERGENCY and EQUIPMENT
The EMERGENCY system is subdivided further into two sub-sub-systems:
LIFE SAFETY and CRITICAL
Sections 517.30-B and 517.30-C cover this topic
These sections require that the EQUIPMENT circuits not be mixed with the EMERGENCY circuits (either life safety or critical). EQUIPMENT circuits can be mixed with NORMAL circuits
The LIFE SAFETY and CRITICAL circuits also must be kept separate from each other and from NORMAL.
There are a few exceptions to the above basically relating to where different circuits meet at equipment
There is another related requirement that states the LIFE SAFETY and CRITICAL circuits must be in rigid metal raceways (no flex, no PVC). The equipment circuit does not have to be.
These are important distinctions. Please be certain to read and understand the code before proceeding.
What is cold-load pick up in power system protection?
Cold load pickup is when you re-energize a distribution system after it's been out for a length of time. The load becomes "cold" and draws more current than it would during normal operation. This is due to things like transformers energizing, capacitors charging, motors starting, light bult filaments heating up, etc. When this happens you can trip out your main breaker again, so you energize with all your feeder breakers open and pick them up one by one, allowing the system to stabilize
Yes, diodes are very polarity sensitive. They conduct in one direction, the forward bias state, where the anode is more positive than the cathode, and they do not conduct in the other direction, the reverse bias state, where the cathode is more positive than the anode. (Assuming you do not exceed forward current or reverse voltage limits.) This is how diodes "rectify", i.e. convert from AC to DC.
This is for normal diodes. Zener diodes are different. They conduct in both directions, but at different voltages. The forward voltage is similar to a normal diode, typically around 0.6V to 1.4V, while the reverse voltage is higher, such as 5.6V, which is how a zener diode can be used in a voltage regulator circuit.
If, however, when you say "polarised", you mean the action of "polarising" an automobile's electrical system, do not even think about it. That technique is no longer necessary since the advent of the alternator. Besides, that technique involves shorting out the battery, which has always been a highly dangerous operation.
What is a ventricular shunt used for?
Ventricular shunt relieves hydrocephalus, a condition in which the ventricles are enlarged.
Why is the current lower when the voltage is higher?
This depends on the circuitry you apply voltage to.
In a circuitry with a fixed resistance of 1 Ohm, 1 Volt would then generate 1 Ampere of Current.
In the same circuitry, 2 Volt would generate 2 Ampere of Current.
Increased voltage will, given the same circumstances, increase the current.
In other words, your question must take something not defined into consideration, or the question may be wrong.
In an attempt to explain why it often works this way I have to look away from fixed circuitries and give real life examples.
By increasing the voltage, the effect of the resistance in an electrical cable is lowered.
In other words, a thinner cable can carry the same "juice" of 360 Volt as compared with a thicker cable of 220 Volt or an even thicker one running at only 120 Volt.
This makes much sense in the fact that thinner cables are cheaper. In a big house, there is much to gain by having access to higher voltages.
A washingmachine, stove, cooker, tumbledryer, dishwasher... All can be made to utilize high voltage instead of low voltage. The current drained goes down, but the wattage remain the same.
The electricity company benefit from less effect of resistance in the cables. They can give more punch with less.
We can also look at a fixed wattage.
If the wattage drained remains the same no matter the voltage, then the current goes down as the voltage rises.
Can 110volt fan motor be used in a 220 volt electric furnace?
It will run, but you will pull more amps than you would while running on a 120v line and it will not run as fast or as efficiently. Bottom line: you'll use more electricity and your bill will be much higher. The motor will also run hotter.
Can old or weak fluorescent lights explode if they're not changed?
Old fluorescent light do not explode. It will go only dimmer and dimmer or sometimes flickering and flashing on/off when it is defective.
What are the differences between active low and active high SR flip flop?
Hello
The difference between an active low and an active high SR flip-flop is that with the active low SR flip-flop, the system is activated when the inputs to system are zeros while with the active high SR flip-flop, the system is activated when the inputs to the system are ones.
Can you use a step up transformer to power your house if you use a sepereate electrical box for it?
Why would you want to do that -where would you obtain a lower voltage supply suitable for supplying a residence.
How many exits in an electrical room with a 480volt 1200amp service?
Per NEC 110.26, two exits are required unless: 1) the working clearance is double what is required, or 2) there is a "continuous and unobstructed way of exit or travel"
How you calculate the proper size of copper bus bar for 1200 Kw load?
You first have to find out what the load amperage is going to be and second, what is the working voltage.
Can you change your home AC fuse with one that has a higher amp rating?
This question could mean two things: A) You want to know if you can make your electrical service bigger. You can. In fact, if you have fuses, your current amperage is pretty low and most modern homes are installing 200 amp circuit breaker panels. Call an electrician to help you with this. B) You want to stop something from tripping, so you want to put in a bigger fuse than what's there. As below, DON'T do this. Fuses and circuit breakers are designed to prevent fire due to excess heat in an electrical system. Overrating the fuse, rather than fixing the problem causing the fuse to blow, will almost certainly cause fire. No, and if you don't know why you shouldn't be doing home electrical repair work. Get a book and read up on this.
== Yes you can, but it is NOT recommended under any circumstances! The "yes" answer is an honest one. You can put a fuse in a circuit that is several times the rating of the one that came out or that belongs in the fuse holder. But doing so is so totally nuts that only a fool of the first order would even consider doing it. Buildings have burned because of stuff like this, and fatalities have been recorded. You've been warned in every way possible. Please do a bit of homework and get up to speed on this kind of thing before diving headlong into it. The recommendations of the previous post are dead on target.
Is energy the rate at which work is done?
Power is the rate at which work is done. Power is defined electrically as current times voltage.
There are different types of energy, such as potential energy (or voltage). Just because the energy is there, doesn't mean work is being performed.
AnswerPower is the rate at which work is done or the rate of heat transfer, expressed in watts, which is a special name give to a joule per second.
Work describes energy in transit between one form and another -e.g. a motor does work when it converts electrical energy into kinetic energy.
Heat describes energy in transit between a warmer body to a cooler body.
Work, heat, and energy are all expressed in joules.
Does a generator produce ac or DC voltage?
NO, generator always generating AC current,when commutator is used,at that time AC is converted in DC.and due to this generator is called dc generator.
