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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
Answer The most common sampling theorem is known from Harry Nyquist, 1889 -1976. It is the foundation of digital audio. In 1928, Nyquist wrote a paper called "Certain Factors in Telegraph Transmission Theory" where he proved that for complete signal reconstruction, the required frequency bandwidth is proportional to the signaling speed, and that the minimum bandwidth is equal to half the number of code elements per second.
Why 230V ac is dangerous than 230V dc?
We know that in a.c frequency changes after 50 sec in the case of 50 hz frequency.
AC or DC voltage, it is the potential difference that counts and also the state of body whether wet or dry which determines the body resistance. It also depends on the insulation of the ground ( an insulator like rubber mat will reduce shock or wearing a boot) Usually DC voltage we encounter is very low voltage of max 50V while AC Voltage is 230V. This could be the reason that electrocution is more in AC than DC. Alternating or Direct potential has no role to play. AC changes so fast ( 50 cycles per second), the fall and rise in potential doesn't has bearing on shock.
A shorted motor would read zero ohms. Note, however, that a meg ohm tester is not an appropriate test device to assess if the motor is shorted, because the difference between shorted and "operational" can often be just a few ohms - you need a low resistance test device - not a meg ohm tester.
What is the boolean expression for a NAND gate?
There are two forms of the NAND gate. Inverted input: Ouput = not Input1 and not Input2 and not Input3 ...
Inverted output: Output = not (Input1 and Input2 and Input3 ...)
Do wind turbines take up very much space?
A wind turbine takes up about 120 square meters including the base and the access road (on average). This is about 10% of a hectare or 25% of an acre. A wind farm of multiple wind turbines takes up about 0.01% of the land it's on. The rest of the land is available for pretty much up all of the uses it had before wind turbines were erected including growing crops, hunting grouse, hiking, snowmobiling or just sitting there.
As a wind turbine generates $5000 to $8000 per year, and most acres have lower revenue than this, it's a great revenue stream for farmers aka multi-revenue stream, small-business owners. And the other 75% of the acre can be used to grow crops.
How much is a miner's salary in Chile?
A former Chilean miner was interviewed by CBC TV in Ottawa tonight. He asserted that Chilean under ground miners were paid about $1 /hour. I was appalled! Canadian miners are being paid from $25 to $35 /hour depending on the remoteness of the mine site.
No wonder mining companies are clamoring to exploit Chile's resources!
What is meant by floating voltage source in the DC voltage system?
In battery technology, Float voltage is the constant voltage that is applied continuously to a voltaic cell under float operation. The voltage could be held constant for the entire duration of the cell's operation (such as in the SLI battery) or could be held for a particular phase of charging by the charger.
I'm not sure there is a term other than "power"; V*A, or the vector sum of real and reactive power is equivalent to the power calculated by multiplying the voltage times the current, ignoring phase shift.
Answer
The product of voltage and current in an a.c. circuit is called 'apparent power', expressed in volt amperes, in order to distinguish it from 'true power' (in watts) and 'reactive power' (in reactive volt amperes).
What is an amplifier of long range radar signals?
Naughty naughty, at least you can try to find the answer yourself on the web without others doing it for you - this is a question in the FT crossword 19th Feb
Calculate the resistance of a 45 W light bulb that has a current of 0.38 A?
The formula you are looking for is R = W/I x I.
It is a sarcastic meme directed at internet comments that love to label anything that they don't agree with as proof of reporter being biased. The incorrect grammar ("bias" instead of the correct "biased") is intentional. It may just be representing the existence of so many grammar mistakes in comments in general or may be hinting towards the low intellect of the posters of such comments.
There are three varieties of pentagrids.
Initial type - 6A7 type (converter).
Grid 1 - oscillator grid,
Grid 2 - oscillator anode,
Grid 3 - screen grid,
Grid 4 - signal grid,
Grid 5 - screen grid.
Development - 6SA7/1R5 type (converter).
Grid 1 - oscillator grid,
Grid 2 - screen grid,
Grid 3 - signal grid,
Grid 4 - screen grid,
Grid 5 - suppressor grid.
Development - 6L7 (mixer).
Grid 1 - signal grid,
Grid 2 - screen grid,
Grid 3 - oscillator injection grid,
Grid 4 - screen grid,
Grid 5 - suppressor grid.
What is the emf induced at zero field current.and what does it signify?
EMF is the voltage across a coil (or motor) due to changes in the magnetic field. If you change the current the coil will generate a voltage (in the opposite direction of the current). So it is not the field but the change that matters.
Electromagnetic Induction
The effective resistance of the capacitor reduces the ripple current through the capacitor making it less effective in its function of smoothing the voltage.
But if the capacitor filter is fed by a transformer and diodes, the resistance of the transformer exceeds that of the capacitor.
The simplest explanation (and therefore not completely accurate, but it will help you understand what happens) is that as the frequency of an AC signal increases the less able a wire is to contain it.
- at very low frequencies, including those of powerlines, the current flows easily through the entire diameter of the wire
- at intermediate frequencies, up to about the AM radio band, the current avoids the center of the wire, only flowing through its surface
- at high frequencies, including those used for TV, a significant amount of the AC signal escapes from a wire as electromagnetic radiation - the shield on a coaxial cable "reflects" this electromagnetic radiation back to the center conductor, preventing its loss
- at microwave frequencies AC will not follow a wire at all and the electromagnetic radiation is directed around through metal pipes called waveguides (analogous to a coaxial cable but without a center conductor, only the outer shield to reflect the electromagnetic radiation)
conventional current flow
Can you use 10 ohm speakers with a 4-8 ohm receiver?
You can use your so called "4 to 8 Ohm's output" amplifier for your 10 ohms loudspeaker. All amplifiers have an output impedance of less than 0.5 ohms. You use impedance bridging when you connect the 10 ohm's loudspeaker. The "4 to 8 Ohm's output" means only that a 4 to 8 ohm loudspeaker will be adequate and not that the output impedance is 4 to 8 ohms! Scroll down to related links and look at "Impedance bridging - Wikipedia".
Full form of AXE telephone exchange?
PCO - PUBLIC CALL OFFICE ISD - INTERNATIONAL SUBSCRIBER DIALING STD - SUBSCRIBE TRUNK DIALING SMS - SHORT MESSAGE SERVICE WWW - WORLD WIDE WEB FAX - FACSIMILE MACHINE EMAIL - ELECTRONIC MAIL AV ROOM - AUDIO VISUAL ROOM VIP - VERY IMPORTANT PERSON PIN - POSTAL INDEX NUMBER PCO - PUBLIC CALL OFFICE ISD - INTERNATIONAL SUBSCRIBER DIALING STD - SUBSCRIBE TRUNK DIALING SMS - SHORT MESSAGE SERVICE WWW - WORLD WIDE WEB FAX - FACSIMILE MACHINE EMAIL - ELECTRONIC MAIL AV ROOM - AUDIO VISUAL ROOM VIP - VERY IMPORTANT PERSON PIN - POSTAL INDEX NUMBER LCM - LOWEST[LEAST] COMMON MULTIPLE HCF - HIGHEST COMMON FACTOR
What are the examples of non linear devices?
"A device for which the output is, within a given dynamic range, linearly proportional to the input" e.g. a spring scale is linear device for measuring weight.
Should you set under the hair dryer and how long?
Answer: Hair dryers are made not to damage your hair because they do not get that hot. You should sit under the dryer until you feel your hair is dry depending on how long or short your hair is you have to make that decision yourself. So don't worry about how long you have to sit under it. It will be safe enough.
