Erasing CDs By Using 150,000 Volts of Electricity 242
ryzvonusef writes "One enterprising individual has created the most secure way to wipe out Compact Discs, by using a step-up transformer and creating a 150,000 Volt pd, whilst a CD rotates in the middle. The sparks arc through the metal in the CD and evaporates it, ripping it all off as the CD rotates. The CD is rendered transparent and unreadable. This may be the most secure method to remove data on conventional recordable CDs used in offices."
Microwave (Score:3, Informative)
Does a thorough enough job, almost everyone has one on hand, takes but 2 seconds an
Re:Please... (Score:2, Informative)
Nope, the metal is a reflective layer allowing the pits in the plastic to be seen by the laser.
http://electronics.howstuffworks.com/cd1.htm
Depending on this top acrylic layer; it may be that depositing a new metal layer on the top of the disc will allow this to be read again.
CD-R have the data stored in the dye layer, the metal is just a reflective surface
http://computer.howstuffworks.com/cd-burner4.htm
Re:For those with less sense and less money (Score:5, Informative)
It's not an intuitive thing, don't worry you're not alone in not immediately seeing the problem.
A magnetron is a kind of RF (radio frequency) transmitter. It converts electrical energy into radio energy. This energy leaves the magnetron and bounces around inside the microwave. The frequency used makes it tend to interact with water molecules, and heats them up, changing radio energy into heat energy. And that's what heats the food. (note that foods with significant water content heat best)
The microwave is tuned just like an antenna is tuned, to maximize the use of energy. Energy the magnetron takes from electricity has to go somewhere. Energy sent into the box that isn't absorbed and converted to heat is reflected back to the transmitter. This is aka a "standing wave". The "Standing Wave Ratio" tells how efficient the energy transfer is.
A high SWR means a large percentage of the input energy is being reflected, and back to the transmitter where it must be used and so is converted into heat. Transmitters expect some of this because the conversion isn't perfect to begin with, but they're not designed to handle a LOT of additional energy to dump, and will overheat. Very high frequencies like magnetrons use are especially inefficient to start with, and so they're usually designed to cool heavily, with fans and fins. The heat you feel coming out the back of the microwave is NOT heat from the food, it's the waste heat off the magnetron. Adding too much to that waste heat can overheat and damage the magnetron, sometimes very quickly.
So, if you put a substantial chunk of metal into a tuned cavity like a microwave oven, it will interfere with the transfer of energy and cause a higher SWR, which can damage the magnetron. Running a microwave without anything in it is not recommended for the above reason, but adding metal into the mix makes matters worse. Placing nothing in the cavity besides a substantial piece of metal is about as destructive as you can be. The denser the metal, the bigger the effect.
Re:In The Ghetto, 01-10. (Score:4, Informative)
Github, Reddit,^H^H^H^H^H^H^H Slashdot... the sewer [4chan.org] is overflowing.