[ARC5] VR Tubes

[Kenneth G. Gordon]

On 8 Nov 2012 at 15:53, Ian Wilson wrote:

> The Amperex data sheet for the 0B2 says:
>   Anode breakdown voltage with illumination of 50-500 foot candles:
>   127 volts max
>   Anode breakdown in complete darkness:
> 210 volts max
> 
> 73, ian K3IMW

Yup. Even a TINY amount of light will lower the anode breakdown voltage 
VERY noticeably. It doesn't take much. There is no need to shine a flashlight 
down into the tube. In fact, the tube doesn't even have to "see" the lamp. 
The tiny bit of light from a pilot lamp several feet away will do the trick.

Ken W7EKB