Electronics Protection

[Slick Fork]

I realize that a tv has more decisions to make then an alarm clock, my speculation was more along the lines of is a $20 alarm clocks circuits really that much more robust then a tv or dvd players?

I think the trouble with most of the computer battery backups is that since they are designed for computers that don't care what kind of signal they're getting the easy way is for them to output in a modified or stepped sine wave. The more expensive ones will output a true sine wave which is what ac motors need.

I saw at future shop the other day a Monster brand power bar with the phase one power cleaner for $99. I guess if I looked at it as $40 for a decent powerbar and $50 for a power cleaner I could justify it if the consensus is that the power cleaners aren't just smoke and mirrors. I think the most fool-proof protection would be one of those "always-on true sine wave" UPS's but that's an investment of another $900.

[midgetwaiter]

Originally Posted by Slick Fork

I realize that a tv has more decisions to make then an alarm clock, my speculation was more along the lines of is a $20 alarm clocks circuits really that much more robust then a tv or dvd players?

Yeah in a way they are more robust. The density of transistors in something like a computer CPU is such that small irregularities can become big problems. You won't see complicated ICs like that in an alarm clock but things like TVs and DVD players are full of them. I'm reminded of a motherboard I had a few years ago that exhibited odd behavior under heavy loads. It turn out that some of the capacitors on the board were faulty and were resulting the in 3.3v line to the CPU dropping to 3.21v under load, then the computer would crash.

Originally Posted by Slick Fork

I think the trouble with most of the computer battery backups is that since they are designed for computers that don't care what kind of signal they're getting the easy way is for them to output in a modified or stepped sine wave. The more expensive ones will output a true sine wave which is what ac motors need.

That's a whole other kettle of fish though. If your power is so bad that you get issues running something "electrical" like a powerhead you need to get an electrician out, they're not very fussy. It's "electronics" like PCs and home theater things like are more likely to need something to regulate power. Even if a switching power supply does not fail it's output can get skewed enough to cause problems.

Originally Posted by Slick Fork

I saw at future shop the other day a Monster brand power bar with the phase one power cleaner for $99. I guess if I looked at it as $40 for a decent powerbar and $50 for a power cleaner I could justify it if the consensus is that the power cleaners aren't just smoke and mirrors. I think the most fool-proof protection would be one of those "always-on true sine wave" UPS's but that's an investment of another $900.

I think $99 is still pretty spendy, again the necessity of these things is being overstated. In 12 years of computer related work I can count the number of times bad power was a problem on one hand. I can't believe that a DVD player is any more susceptible to this type of thing than a PC and aquarium equipment is most definitely not.

[mike31154]

The front end of most any product with a processor these days is a power supply that converts the line AC into various levels of DC voltage. Pretty much the same idea with most television and radio appliances. The DC is then again internally converted back to various AC voltages for clock circuits etc. It's this front end that will take the brunt of any power irregularities. Most of these are additionally fused so that the very sensitive electronics downstream of all this are fairly well shielded. I'd hazard to guess that it would take a substantial spike, such as lightning to really damage any of this stuff and if that happens, no surge protector in the world is going to help.

Once you open the case of one of these items, it doesn't take much to damage the goodies on the printed circuit board. Walk across the carpet in a dry room, touch an IC on the board and that could be the end of it. Thats why repair technicians wear little wrist bands that are grounded when they're working on this stuff and it's also why sensitive replacement components come in static proof packaging.

[banditpowdercoat]

I have had wiring problems in my house. Acctually the Neutral came loose in the meter base. WHen that happens. some things get low voltage, where others, like the electronics, can get close to 240v. My computer, which was protected by a good APC power bar with surge protection, it survived. The powerbar did not, but the computer and related items did. In that incident, I lost a 52"TV, Yamaha Receiver, Paradigm subwoofer, Denon DVD, VCR, microwave, 3 clocks, and a crapload of screw in flourescent lights....

[mike31154]

That's a fault mode I haven't seen very often. Sorry to hear about the equipment losses. With a loose neutral at the meter there would be a higher resistance in virtually all circuits in the house. This should mean excessive heat in some cases? Lucky the place didn't burn down around you.

[banditpowdercoat]

Originally Posted by mike31154

That's a fault mode I haven't seen very often. Sorry to hear about the equipment losses. With a loose neutral at the meter there would be a higher resistance in virtually all circuits in the house. This should mean excessive heat in some cases? Lucky the place didn't burn down around you.

ya, Im an electrician, so knew what it was right away. But just got home form work, and the house was dark, and wife just ran outside with the daughter as I pulled up screaming the lights are flickering, the washing machine is screetchng, the place is haunted!!!!!!!. Was in the middle of giving her a bath. I instantly turned main breaker off and started checking. Thank god for house insurance. Got everything replaced.

[brizzo]

http://www.ncix.com/products/index.p...cture=OPTI-UPS