This tube is very hard to find. It’s compact size and it’s connection socket, similar to the car brake light bulb makes it the stangest tube I’ve ever seen.
![](https://madexp.com/wp-content/uploads/2018/01/s-l1600-1024x768.jpg)
MS-13
There is very few information about it and it’s usage… it’s from the M-series of professional tubes so I could guess it was used in some kind of portable precision survey equipment.
![](https://madexp.com/wp-content/uploads/2018/01/s-l1600-2-1024x768.jpg)
MS-13 light bulb type base
It’s base looks very similar if not equal (I must try) as a car light bulb.
![](https://madexp.com/wp-content/uploads/2018/01/s-l1600-3-1024x768.jpg)
The tube and it’s datasheet
I don’t know russian so I just know how to recognize the most important parameters to make working the tube. I’ll appreciate more info’s about this tube, feel free to contact me at “l.i.papadopol at gmail.com”
-Working voltage 720-780V
-Plateau lenght 200V
-Plateau slope 0.15%
-Load resistance 8-15MOhm
-Working temperature -40° +50°
-Lenght 100mm diameter 21.5mm