J-F

4/3/2009 5:04:18 PMUnknown tubes

I found in my stock a RCA radiotron 868 tube (4 pins) and a Rogers A/C 551 (look like 24A with globe shape).

I don't know what they are.

4/4/2009 7:18:15 PMNorm Leal

An 868 is a 4 pin photo tube. This tube is used to detect differences in light. Can be used to detect something crossing a light beam. The 868 was also used to detect the sound track on film.

A 551 is same as 35 tube. Looks very similar to 24A but is remote cutoff. It takes a greater negative grid #1 voltage before the tube stops operating.

Norm

:I found in my stock a RCA radiotron 868 tube (4 pins) and a Rogers A/C 551 (look like 24A with globe shape).
:
:I don't know what they are.

4/4/2009 7:52:54 PMNorm Leal

An 868 is a 4 pin photo tube. This tube is used to detect differences in light. Can be used to detect something crossing a light beam. The 868 was also used to detect the sound track on film.

A 551 is same as 35 tube. Looks very similar to 24A but is remote cutoff. It takes a greater negative grid #1 voltage before the tube stops operating.

Norm

:I found in my stock a RCA radiotron 868 tube (4 pins) and a Rogers A/C 551 (look like 24A with globe shape).
:
:I don't know what they are.

4/4/2009 9:21:40 PMPeter G. Balazsy

testing only

4/4/2009 10:31:08 PMJ-F

Cool thank you, will keep them only for display...

:Hi
:
: An 868 is a 4 pin photo tube. This tube is used to detect differences in light. Can be used to detect something crossing a light beam. The 868 was also used to detect the sound track on film.
:
: A 551 is same as 35 tube. Looks very similar to 24A but is remote cutoff. It takes a greater negative grid #1 voltage before the tube stops operating.
:
:Norm
:
::I found in my stock a RCA radiotron 868 tube (4 pins) and a Rogers A/C 551 (look like 24A with globe shape).
::
::I don't know what they are.