Hola Sergio,
Una posibilidad.
Buena suerte y saludos del Oso ¶:^)

--------------------------------------------------
Note added at 9 mins (2006-07-18 23:04:16 GMT)
--------------------------------------------------

Otro ejemplo:

"...The Eppendorf ***Electroporator*** is used for the electroporation of bacteria and yeast cells where pulses of very high electrical field strength are applied to samples of small volume and high resistance. The ***electroporator*** contains a capacitor that can be selectively charged to a voltage between 200 and 2,500 volts. This capacitor is then discharged into a resistor to create an exponential discharge curve. The exponential pulse created by the system is applied to a small disposable cuvette containing a biological sample. The results of the electroporation can be transferred to a printer or a PC.
In contrast to devices from other manufacturers, the Eppendorf Electroporator has an integrated cuvette holder. ..."

http://www.eppendorf.ca/utilities/download_pdf.asp?DR=downlo...

The electroporator is easy to use. The device does not have components which have to be maintained by the operator.

The construction of the electroporator minimizes the risk of arcing even in the case of invalid high salt concentrations and maximum voltage. Even in the extremely improbable case of arcing in the cuvette, no bacterial suspension leaves the cuvette and pollutes the device.

The Eppendorf Electroporator corresponds with valid UL regulations and is CE certified.