Posted on 09/12/2016 8:41:16 PM PDT by Swordmaker
Zot of a different order of magnitude
The cheapy surge protectors use Metal Oxide Varistors. They essentially vary their resistance with the voltage. When a surge comes through they short it to ground. Once. The next surge will go right on through. So, you get a lightning strike that blows through the MOV, then the air is an ionized conductive plasma and a secondary strike comes through, something that happens frequently. ZAP! Two surges in a row. First is shunted to ground, second goes right on through the cheap surge protector.
A teaspoon of iron filings in the cooling vents of any PC should work equally effectively.
The Data is still there.
Data ports are buffered, so the buffer is blown but the data remains.
Better to destroy the power bus. But still damage is limited to the weakest point. The data can still be recovered with enough resources.
Why not just zap the whole device with with a high voltage stun gun?? That is more damaging.
So you’re supposed to use this USB Kill gizmo to “test” your computer to see if it’s vulnerable to a USB power surge. But the way you find out is if it kills your computer or not.
I don’t think they’ve thought this whole thing through...
The real truth is that this device was designed for malicious purposes. Regardless of what the author or the manufacturer says. You hand it to someone you don’t like and you tell them to checkout the pictures or whatever and then you walk away. That is what it is designed for.
When I saw the price in rupees, my first thought was a memory of an experience with some nice people from that subcontinent and their feeble attempt to freeze and ransom one of my computers.
Another freeper told me they were prolly moonlighting Windows employees.
Now we know what fell out of her pant leg.
That’s exactly my point. The “volt” is a unit of EMF, not “charge.”
Using the “volt” as a unit of charge is like saying, “How much water is in this jug? Five pounds per square inch.”
No, no, no! It's not for you to use on YOUR computer. It's for you to use on your buddy's computers. . . heheheheh.
Actually, it's for the manufacturer to test their own products.
Probably an inverter converting the DC USB supply to AC, feeding into a voltage multiplier charging a capacitor to 240v, at which time a thyristor is opened to discharge the capacitor back into the USB port, after which the cycle repeats. The frequency would depend on how much current can be drawn from the port and how big the capacitor is.
See here.
If you found this gadget in the parking lot, what would you do?
To paraphrase a famous 'Rat pol, you have to plug it in to see what's in it ...
Of course, if you have an Apple computer, nothing will happen.
But then, what if you found a different USB in the parking lot, and you plug it in and find it contains your agency's personnel database, among other things. You click this, that, and what not. Soon, your computer is uploading everything to which you legitimately have access across the big pond to the PLA ...
Metal Oxide Varistor surge protectors are cheap, but do not really provide good protection since the MOV’s degrade over time. There are better surge protectors using avalanch diodes, but they are not cheap. In the event of a major surge or lightning strike, avalanch diodes will self sacrifice but still in most cases save equipment. These are used often for servers and data centers in addition to UPS’s.
Okay, so the reality is that it destroys the USB circuit not the whole computer. Bad, but that doesn’t mean it wipes out the hard drive or other peripherals.
So its a “smart” capacitor...
Yeah. I would think that most USB ports would have such protection.
The peripherals and their connectors had to withstand up to 2,000 volts not just 240V. But the charge was delivered from a specified capacitor charged to that voltage, per the specifications. It modeled the human body, and was to ensure that our device would survive if some human joker scuffled their feet across the carpet and then picked it up and drew a spark.
Possibly there's more capacitance in this USB device, thus more total stored charge, albeit at a lower voltage.
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