They use mercury lamps. I took one apart to use the lamp as a wavelength standard. Don't try that at home, the sterilizers have interlocks to prevent accidental eye and skin exposure.
Yes. Don't do it. Buy the nice little mercury-argon lamp from Ocean Optics.
First of all, the mercury lamp is dangerous, for real. Second, the newer sterilizer pens contain complicated interlock circuitry, making it impossible to figure out how to actually get the lamp to turn on by itself. I got one lamp to light up from an external power supply, then set it aside and bought a few of the Ocean Optics boxes.
As a wavelength standard, it was also a poor configuration -- most of the light can't be directed where you need it, whereas the Ocean Optics produces a nice compact beam and has a fiber optic connector.
Aha, the company name changed. But I've bought these under the Ocean Optics brand, and they've always worked fine. Note that they have a variety of elements, not just mercury. If you don't need great gobs of photons, a small neon lamp is a lot more friendly to play with, still involves dangerous high voltage, but no UV. The NE-2 lamp is a common one, available from electronic parts suppliers.
I found the circuit of the sterilizer pen to be impenetrable, as it contains a microcontroller, which is a "black box" to me. I think they wanted to make it hard to jimmy.
