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Volt Transient
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Finding the Right Surge Protector for Your Computers and Gadgets
The main function of a surge protector is exactly what the name suggests: to protect electronic equipment (particularly computers) from electrical surges.
Power surges occur when an electrical current suddenly increases voltage significantly higher than the designated level. In America, the standard voltage for household wiring is 120 volts. If the voltage rises high enough above that level, the resulting electrical surge can cause considerable damage electrical equipment.
Computers are particularly vulnerable to electrical surges, simply because they have so many components that are highly sensitive to voltage extremes. Electrical surges can shorten the life of computer components, wipe your hard drive, or even destroy your entire system.
A good surge protector is a must for your computer, due to the extreme vulnerability of computer components. It's also a very good idea to use a surge protector for any other expensive electronic equipment, such as an entertainment center, as using a surge protector here will extend the life of the components.
Standard surge protectors work by sensing surges in electrical energy, and then diverting the excess electricity into the outlet's grounding wire.
Types of Surge Protector
There are three basic types of power surge protector: power strips, surge stations, and uninterruptible power supplies.
Power strips (which allow you to plug half a dozen or so electrical items into one outlet) range in price from around $5 to $25. These provide a very basic level of protection—they're generally not suitable as the sole level of protection for a computer, but usually provide plenty of protection for most inexpensive items.
Surge stations provide a good level of protection for a personal computer. They're larger than power strips but can fit underneath a computer or sit on the floor. These offer much better protection than power strips, and usually allow you to protect your modem as well. They cost anywhere from $30 to $100 or more depending on how much protection you want.
An uninterruptible power supply combines a surge protection unit with a continuous power supply. These work by converting a supply of AC electrical energy to DC, then storing the DC energy on a battery. The unit then converts that stored DC power to AC power again, providing an uninterruptible power supply that your computer can use if your power goes out. Most units give you several minutes' worth of stored energy that gives you enough time to power down your computer to protect its components from the effects of sudden power loss. You can expect to pay $150 or more for one of these.
How to Choose the Right Surge Protector
Choosing the right surge protector from these three types is simple, requiring only that you one that's suitable for the cost of the equipment you want to protect. If you're choosing a surge protector for your kitchen appliances, a cheap power strip will do the job just fine. On the other hand, if your computer needs protecting, a power strip is not enough.
The harder part is choosing the brand. Unfortunately there are many products on the market that are all but worthless, and it can be difficult to find one that will do the job.
Price is one indicator of quality for power strips, in particular. In general, if it costs less than $10-$15, chances are it's not going to provide any real protection. Here are a few more signs of quality you can look for:
- Choose a surge protector with an indicator light that is lit when the unit is working. Without this feature you have absolutely no way of knowing whether your surge protector is providing any protection.
- Check the item's Underwriters Laboratories Rating. The UL is an independent company that tests electric and electronic products. If the product in question doesn't have an UL rating, don't buy it.
- Choose an item that meets UL 1449. This is UL's minimum performance standard. Surge protectors that meet these standards are labeled as "transient voltage surge suppressors." This is important particularly for power strips, because a strip might have an UL rating for its extension cord performance, but won't have surge protection capacity unless it's actually labeled as such.
- Choose a unit with a low clamping voltage (the level at which the surge protector diverts energy)
- Look for a surge protector that provides a high energy absorption rating. Higher ratings allow the unit to absorb more electricity before failing.
- Choose a unit with a low response time (ideally less than one nanosecond). This is the delay between the power surge and the unit's response to the surge.
- Finally, look for a unit that comes with a guarantee. The best surge protectors provide a replacement guarantee for your computer, and these are a good indication that the manufacturer has a high level of confidence in their product.
About the Author
About Author:
Brain Jenkins is a freelance writer who writes about products for the workplace such as Surge Protectors
Explain, with the aid of a suitable diagram, what is meant by the term companding. Why is it?
a)Explain, with the aid of a suitable diagram, what is meant by the term companding. Why is it used in PCM telephony?
b)An A-law compander operates over the range -V to +V volts.
(i)Give, in terms of V, an expression for the maximum absolute voltage error that can be caused by a single bit and explain your reasoning.
(ii)If V is 5 Vand a transmitted word 11100011 is received as 11101011, what is the absolute voltage error introduced into the decoded signal by this bit error? Give a brief
explanation.
c)Explain, in your own words and with the aid of appropriate charts from a spreadsheet model of delta modulation, the fundamental principle and characteristics of delta modulation
covering the phenomena of slope overload and the transient period. You are not required to go into the details of transmitter or receiver structure.
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Microsemi Announces Highest Power SiC RF Power Device for UHF Radar Applications
IRVINE, Calif. -- Microsemi Corporation , a leading manufacturer of high performance analog mixed-signal integrated circuits, high reliability semiconductors and RF subsystems, announced today a new 2,200 watt peak RF power silicon carbide transistor, extending its market leading portfolio of silicon carbide devices for high power UHF Band pulsed radar applications.
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