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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
Is it better to leave an electronic device on or to turn it on and off?
It depends on the device, power consumption and physical environment.
Computer equipment: Generally happier when left powered on with the exception of the hard drive and monitor (both of which have sleep modes available). The hard drive has moving parts that will eventually wear out if left running for prolonged periods. The solid state components have delicate soldering points that are prone to cracking if heated and cooled repeatedly.
Televisions: Tube televisions are best left off when not being watched. It saves power and causes less wear to the phosphorous coating in the tube. LCD TV's are best put to standby mode. Plasma screen TV's are MUCH better off when turned off -- the plasma screens have about a 7-year lifespan under normal conditions, and are very expensive.
Misc: Older electronics using vacuum tubes are way better off left on for less wear on the components, but will suck a lot of power. Anything with moving parts is best turned off such as DVD players, XBox consoles, or anything that reads moving media.
Environment: Humidity is an electronic nightmare. Leaving the component running will help to fend off the ravages of moisture, but make sure to clean any exposed vents regularly with compressed air. Vibration is very bad for electronics in an on state. If you live near railroad tracks or on a ship, electronics will be better off if you turn them off while not using them. This is especially true for high-heat components such as amplifiers, televisions, and computers.
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Another concern is that many audiophiles feel that audio equipment, especially an amplifier, does not sound its best until it has come to a stable, warm operating temperature. That can take an hour or more.
The voltage spec'd on these units is pretty loose and the valves are desiged to cope with that range. For example, the 750 mv unit at :
http://www.honeywellcentral.com/product/0-85267-87879-1.html
is rated 600mv to750mv open circuit. Measured in circuit, the output could be even lower than 600mv and be OK .
What does it mean if a digital filter is IIR?
We can divide filters two types based on the length of the impulse resopnse 1. FIR where the impulse responce is finite 2. IIR where the impulse response is infinite
IPC means Inter Process Communication. Two processes can communicate with each other using these Mechanism. They can use shared memory ,Pipes FIFO's Semaphore,Signals.They can send signals and they can kill each other.They can stop the process by sending the signal.They can share data using Shared memory.They can send messegs using Message Queue.Money advantages of IPC's are there.
IPC also means Indian Penal Code. It is a document that covers almost all the crime happening in the society. It is a piece of British colonial legislation dating from 1860.
Why does the US run at 120V when some of the world runs at 240V?
Technology, current at the time of US electrification, locked the US into 110, then 120 volt outlets. Europe's electrification came later, and proceeded in response to advanced technology. The US was too deep into the 110/120 volt infrastructure to upgrade. The US has remained in this situation ever since.
House voltage was first determined by Thomas Edison who set it for optimal performance of his equipment.
Additional Information:
The United States distribution system actually provides a 240 volt residential service in the form of two 120 volt conductors and a neutral conductor. You can see this if you look inside your breaker panel. When a load is applied from either 120 volt conductor to the neutral (as is the case for typical receptacles, lights, and so forth) it is using 120 volts.
However, when a load is applied from one 120 volt conductor to the other, without using the neutral, the voltage being used is the sum of both 120 volt conductors (240 volts). This is the case for many water heaters, air conditioners, electric furnaces, clothes dryers, and so forth.
So equipment that is connected to strictly 240 volts is connected with only a two wire cable plus a safety ground wire. (For example 240 volt base board heaters use this.) The only time a cable with three wires plus safety ground is used is if 120/240 volts is needed in the equipment. (For example kitchen ranges or washing machines which have time clocks or programmers that require only a 120 volt feed.)
For systems outside the US, receptacles are 240 volts. Lower voltages tend to be safer, which is why in the US, you are receiving 240 volts at the home box and 120 at receptacles, instead of the thousands of volts generated by the power plant.
Power is transmitted over High Voltage cables - usually above 10K Volts. The power is then stepped down before it reaches consumers. Outlet power in the US is 120 volts, increased from 110 volts sometime around 1950.
The US system theoretically could be made as good or better than the European system with no infrastructure change, except appliances and consumer structuresthemselves (collectively costing home owners billions). US houses get 240 volts at the panel. If wall outlets all were fed with 240V you'd have the lower current and higher power advantage of the European system and it would be safer too, since each "hot" would still be only 120V from ground (not 240V) which keeps the reduced shock hazard advantage. Of course it is still possible to touch the two hots.
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The origin of the 120 volt standard dates back to the feud between George Westinghouse and Thomas Edison. The first public electricity utilities were set up by Edison, whose concept was that there would be a power station (Coal fired) at the end of every street, supplying low voltage DC. Westinghouse came up with the idea of using AC, which can be transmitted over long distances from a small number of giant power stations. Edison worked to get the concept banned to protect his system by claiming that it would lead to the use of dangerously high voltages.
The result of this public debate was that the US opted for the low voltage, but using AC as Westinghouse recommended.
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A zener diode has a voltage when it reachesbreak over it may be 5v 12vor other voltage as manufactured. The manufacture will produce a 5v zener or is it? This voltage can change from device to device but the mean or nominal voltage will be as close as 5v as possible. So when buying a 5v zener do not expect 5v absolute but a nominal 5 v
ZENERS are designed for a specific voltage [ THEREFORE NOMINAL] as mentioned above . depends on the voltage required it can be bought within a specific voltage -/+ a % of the breakdown
In describing waves is the mathematical symbol used the waves period this quantity has units of?
T, seconds
Ohm's Law: V = IR (voltage = current times resistance).
Ohm's Law: V = IR (voltage = current times resistance).
Ohm's Law: V = IR (voltage = current times resistance).
Ohm's Law: V = IR (voltage = current times resistance).
What types of material cant a scrap heap magnet move?
Anything that is not magnetic, so pretty much anything that is not primarily made of steel. That would include plastic, glass, copper or brass, cloth or paper, etc.
The capacitor is used to store the charge applied to it.
This stored charge can be used to absorb voltage spikes and voltage drops.
Answer
It's a misconception that a capacitor stores charge. In fact, it stores energy. The net charge on a fully-charged capacitor is the same as on a fully discharged capacitor.
What is the difference between resistance box and rheostat?
Resistance box will provide resistance of discrete values such as 1, 2, 3 ohms or 0.1,0.2, 0.3 ohms. So interim values are not possible.
But rheostat gives a chance to vary the resistance continuously. It may be 5 ohm or even 5.769 ohm.
So just to fix current for a specified value such 1.5 ampere resistance box will not be suitable where as a rheostat is the most suitable.
A semiconductor device that is particularly sensitive to changes in temperature, permitting it to serve as an accurate measure of temperature.
By definiton, a diode lets electrical current flow only in one direction. A RECTIFIER DIODE is basically the same thing. It is used mainly for power supply operation and can handle higher current flow than a regular diode. Diodes are rated from milliamps to as high as 100 amps per diode depending upon the diode style and amperage rating. A recitifier diode is the same as a "Power diode". Diodes are mainly used to change AC (alternating current) into DC (directo current) which is used by batteries and etc.
Biased listening occurs when an individual listens to a superficial level and typically misinterpret the message.
How does mobius coil generate electricity?
A mobius coil doesn't generate electricity by itself. If power is applied to function the mobius coil, positive and negative fields applied in opposing direction, then they cancel each others field out supposedly producing a scalar wave. A scalar wave is part of the Quantum theory of particle-wave duality.
Difference in potential between two points. Like the voltage of an energizer AA battery is 1.5 volts BETWEEN its terminals. If you place two AA batteries in a flashlight, the voltage of the series combination of AA batteries from one tip to the other is now 3 volts.
What is the apparent rule for combining resistances in parallel circuits?
The effective conductance is the sum of the individual conductances. "Conductance" is the reciprocal of resistance. Expressing the rule in terms of resistances:
1 / R = 1 / R1 + 1 / R2 + 1 / R3 ...
Where "R" is the effective (combined) resistance, and R1, R2, etc. are the individual resistances.
What are the advantages and disadvantages of clipping circuit?
In what context? Assuming signal transmission, the main disadvantage of a clipping circuit is that the data transmitted at values outside the circuit's range will be "clipped" (for example, if the clipping value is 20V, and the signal is 23V, the output will be 20V). This is esp. visible with audio circuits, and with electron tube circuits in general.
The main advantage, at any rate, would be that a clipping circuit would serve as, say, an overvoltage protection for sensitive devices. But that is a bit of guessing on my part. If the circuit (or circuits) are to be designed properly, I would say that a bridging circuit should be built instead - a circuit that would "shake hands" between two other circuits, bringing their respective levels to a level common for both, or by translating between the two.
Difference between unbonded strain gauge and bonded strain gauge?
The essential difference is that the bonded strain gauges are bonded on to the specimen whose strain is being measured whereas the unbonded strain gauges are not bonded on to the specimen.
As the bonded strain gauges are well bonded on to the specimen, the entire strain being experienced by the specimen is transferred to the strain gauge. However, the bonded strain gauges are affected by temperature changes and also due to transverse strains.For transverse strains and ambient temperature compensations, suitable circuits for compensation can be used using Wheatstone's bridge.
The unbonded strain gauges cannot transfer the strain of the specimen to the strain gauge and hence it is used mainly for displacement, or pressure or force transducers. It is least affected by transverse strain and temperature compensation of unbonded gauges cis automatically eliminated using Wheatstone's bridge.
