XF86

[TonyTecson]

is this tube the 2.5 volt version of the EF86, asking for confirmation...
found several of these tubes on a dumpsite...😀

 

[JonSnell Electronic]

European system after 1934 (pro-electron)
See also: Type Designation Code from "Preferred Types of Electron Tubes 1967".
1st letter heater indication
0 tubes without filament
A 4 V AC parallel connection
B 180 mA DC
C 200 mA AC/DC series or parallel connection
D <= 1.4 V DC dry-battery, parallel connection
E 6.3 V AC or carbattery, parallel connection
F 13 V carbattery
G 5V AC parallel connection
H early: 4V DC battery. later: 150mA AC/DC series connection
I 20V AC/DC parallel connection
K 2 V battery
O 150 mA AC/DC series connection
P 300 mA AC/DC series connection
U 100 mA AC/DC series connection
V 50mA AC/DC series connection
X 600 mA AC/DC series connection
Y 450 mA AC/DC series connection


So 600mA heaters for series connection.

I can find no record of this type of thermionic valve.

 

[TonyTecson]

I can find no record of this type of thermionic valve.

neither can I, i guess the better way would be to try it in a circuit using the EF86, thank you...

 

[adalin]

Or ask someone to trace the tube in a curve tracer

 

[DeathRex]

Does it look like a EF86?

 

[DF96]

I think it is a 2.1V 600mA heater version of EF86. Probably quite rare?

 

[Abszero]

Use DC adjustable and start at low voltage. Use a 1ohm series with the filament and measure current through the circuit. When you get to 600mA measure the filament voltage. This is what you should use.
Unless you already figure it out.

 

[TonyTecson]

Does it look like a EF86?

it does...

 

[TonyTecson]

I think it is a 2.1V 600mA heater version of EF86. Probably quite rare?

if other tubes with prefix starting with "X" is to be considered, then i would say yes, about 2.5 volts...

tube at the left is the EF86 pulled out from a tube scope and the four other tubes are the XF86.....