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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 is there still current flowing when a switch is off?
If everything is connected and working correctly, there shouldn't be (probably). The purpose of a switch is to interrupt current.
-Is this new? Has it been wired correctly? Are you sure?
-How are you measuring this? Is the amount of current flowing within the error margin of your measuring equipment? Are you measuring correctly?
-Is there a "night light" feature to the switch (LED/small light that will always be on when the switch is off)?
-Is this a dimmer switch? Is it actually off, or just turned down so the lights don't appear to be one?
-Is current balanced between the neutral and the phase wire (ie do you have something causing a low magnitude ground fault)?
How do you differentiat dc motior and ac motor physicaly?
if you power an ac motor with dc or a dc motor with ac you will likely start smelling smoke and the motor will be damaged. If the motor is marked "3-phase", "shaded pole", or "induction" it is an ac motor!
BTW, there are ac/dc motors that will run on both, they are wound very much like dc motors but a bit differently.
Why do you connect electrical lamps in series?
If you are referring to house wiring, then you don't normally connect lamps in series with each other; they are normally connected in parallel with each other. When lamps are connected in parallel, each lamp is subjected to the same voltage; providing this is the rated voltage of each lamp, them each will operate at their rated power.
If you did connect lamps in parallel, the you would find that the lamps with the higher power ratings will be dimmer than the lamps with the lower power ratings -which is not what you might expect!
What is chemical earthing and how it is done?
chemical earthig is that type of earthing where low water level mostly used in hilly areas
If a differential amplifier stage has collector resistors of 5.1k ohms and if ic1 equals 1.35ma and ic2 equals 1.29ma the differential output voltage is 0.306 volts.
(5.1 * 1.35) - (5.1 * 1.29)
What happens if you increase the current in an electomagnet?
As current increases, the electromagnet strength will increase.
How do you calculate the current flowing through a heater?
The formula you are looking for is I = W/E. Amps = Watts/Volts.
transformer coupling
Why should the clearance between power and telephone cables not be less than 300mm?
Telephone signal is more prone to EMI (Electro Magnetic Interference) effects of Electrical energy flowing through the power cable. To avoid such EMI effects, telephone cable is laid little bit away (300 mm at least) from the power cable.
What is a distortion analyzer?
A distortion analyzer is an electronic test instrument that measures the accuracy of an electronic circuit at reproducing a wave. For instance, an audio amplifier might have a sine wave input to it, and the distortion analyzer measures how close the output is to a sine wave. If the output is clipped, the wave will be distorted, and the analyzer will measure the amount of harmonics present.
The analyzer does this by supplying a low distortion sine wave test signal which is connected to the device under test. The output from the device is connected to the input of the analyzer where the original input signal is filter out with a precision notch filter. Anything left over after filtering represents distortion components and noise. Amplifiers will frequently have a "Total Harmonic Distortion plus Noise" specification which is an accurate term for the quantity measured by a distortion analyzer.
There are many manufacturers of distortion analyzers. The Hewlett-Packard models 331a and 333 are laboratory standard instruments. Other notable manufacturers are Sound Technology Corporation and Textronix.
How much do you get paid technical engineering?
it depends if there are smart and have better qulification then the rest and a good team player then you will get paid probably about £57000-£65000
Is there a battery that never dies?
http://www.nextenergynews.com/news1/next-energy-news-betavoltaic-10.1.html
power plant
solar cell
Where is the relay or circuit for the locks on a 94 Dodge Caravan?
The relay for the locks is usually located in the fuse panel (usually lower left of the steering wheel) and is one of the larger rectangular boxes plugged into the fuse panel.
What is the voltage of a cat5 cable while it's communicating?
One person has suggested: "Its a very small amout of voltage. Usually microvolts." This is somewhat inaccurate, but only by a factor of around 1,000,000 times too small. A more accurate number is: "around 2.5 volts peak differential". Your typical consumer LAN uses 10Base-T signalling over a Category 3, 4 or 5 twisted-pair cable. The 10BASE-T transmitter output voltage specified in the standard (IEEE 802.3-2005 14.3.1.2.1) requires a peak differential voltage of 2.2 to 2.8 V into a 100-Ohm resistive load. There are IEEE technical discussions (March 2007) about reducing it to below 2 volts, perhaps using a "negotiation" protocol for devices on the LAN to choose a lower voltage if they are capable.
What are the periodical checks to be carried out on a Diesel Generating set?
* The quality of the diesel fuel.
* The typical checks you would make on a diesel engine such as the cleanliness of the fuel injection system, belts, compression ratio.
* Will the diesel engine start easily and automatically (in the case of an auto-on system). Is the battery good, proper fluid levels.
* Bushing temperature (while the generator is operating) and lubrication.
* Is the generator putting out the proper voltage?
* Cable lug torque? * If it is DC, then check the brushes, and commutator. * If it is 3-Phase, check the voltages of each phase (<1% deviation phase-to-neutral, or ground) * If the diesel motor is going through a gearbox, check the integrity of the gears, lubrication, wear, etc.
* Look at the 'Related Links' below...
When induction motors is used for power factor correction what is called?
I'm not sure I've ever seen an induction motor used to correct power factor; it is usually the induction motors that are causing the poor power factor. "Power factor correction" is usually accomplished by adding capacitors to the system to counteract the inductance of large motors.
Why is ideal resistance of a voltmeter infinity?
generally voltmeters are connected in parallel in the circuit.If the voltmeter resistance is lower as it increases the current rating,because by connecting parallel we are decreasing the resistance,so if the voltmeter resistance is not too much higher it leads to burning of the meter,For that we can conclude that the in ideal the voltmeter has infinite resistance.
The devices thgat do not follow ohms law?
All devices follow Ohm's law. Ohm's law states that voltage is equal to current times resistance. This is always true. DC, AC, RF, whatever. Resistance, capacitance, or inductance, whatever. Its a matter of proper perspective, and its a matter of taking everything into account.
Some devices do not have a linear response to voltage or current.
Take the light bulb, for instance. If you measures its resistance you can calculate what you think its current and power would be at a certain voltage, and you would be wrong, unless you also considered temperature. This is because light bulbs have a very dramatic resistance to temperature coefficient. As an example, a 40W applicance bulb might have a cold resistance of 27 ohms. That translates to 4.4A or 533W, with a 120V source. The truth is that the 40W bulb has a hot resistance of 360 ohms, giving an on current of 0.333A and an on power of 40W, with a 120V source.
For another example, look at the diode. Initially, it appears to have high resistance. When the voltage across it reachs the forward bias voltage (or the reverse bias voltage for a zener diode) it starts to conduct and draw current. As you increase the current, you note that the voltage is relatively constant. That is certainly not a resistor - the diode's resistance is increasing as current increases so as to make the voltage be somewhat constant. You can still calculate voltage, current, resistance, and power, but only at each point of observation.
For the last example, though not really an example of non-linear resistance, consider the capacitor. In a DC circuit, the capacitor initially has zero ohms resistance, but it quickly rises to infinity ohms depending on current and capacitance. In an AC circuit, this a much more interesting and useful case - the capacitor stabilizes at a certain capacitive reactance, and the operation of the curcuit complies with Ohm's law, but lo and behold - you find that the current is no longer in phase with the voltage. While this complicates calculations, nothing changes the fact that voltage is current times resistance. That is an immutable given - your task is to learn how to measure it correctly.
In each of these cases, and in any other case, Ohm's law applies, but it applies in a certain way, under a certain set of circumstances. The bulb has 360 ohms of resistance at 120V, giving 0.333A and 40W. That is very clear. What you must maintain equally clear is that resistance is not always a constant - and you must consider that inconstancy every time you change the conditions of the circuit.
AnswerOhm's 'Law' is somewhat of a misnomer, because it is not really a universal law because it only applies to a small range of conductors.Ohm's Law only applies when the ratio of voltage to current is constant for variations in voltage. Devices that follow Ohm's Law are called linear or ohmic; those that don't are called non-linear or non-ohmic. Most metal conductors are linear, but some are not. For example, tungsten does not obey Ohm's Law because its ratio of voltage to current changes as the voltage applied across it changes -in other words, tungsten is non-linear. Electronic devices, such as diodes, electrolytes, and gases are all non-linear and do not obey Ohm's Law.
Having said that, the ratio of voltage to current will always tell you what the resistance of a device happens to be for that particular ratio and, so, the equation R = V/I applies to all devices whether they are linear or non-linear. However, this equation is not derived from Ohm's Law, but from the definition of resistance.
Can a non polarized capacitor be connected to a direct current circuit?
Yes, you can connect a polarized capacitor to a direct current. Make sure you get your polarization is correct.
A non polarized capacitor can be connected in a DC circuit as well. "Non Polarized" just means it does not matter which side of the capacitor is positive. If you attempt to connect a polarized capacitor in a DC circuit backwards, you will know when the capacitor explodes.
No. A diode conducts in one direction but not in the other.
What will be the starting current of a 335hp Sqcage motor on no load?
Across the line starting of a motor can be as high as 300% of the full load amps.
