Steve Anderson wrote:Electrostatic CRT deflection is generally used in 'scope applications where the vertical gain and the timebase are varied over quite a range whilst in use. In an electrostatic CRT you'l usually have five more electrodes than a magnetic CRT, two pins (electrodes) for horizontal deflection, two more for vertical deflection and one more for focus. That's very general, but generally true. There are a few odd CRTs that were deflected horizontally with an external coil, but vertically with plates - but they are oddballs and rare (thankfully).
The advantage for low-speed applications (NBTV/SSTV) is the amount of power required for deflection and focus is almost insignificant. The downside is the voltages required can be as much as 500V, usually less though for most common electrostatic CRTs, say 300V.
If this were your first foray into CRTs try to find a smaller (say 3") tube, the 3" DG7-32 is still widely available in Europe and not that expensive and easy to drive - getting the socket for it can be a different matter - but there are ways around that.
Steve A.
Postscript:- Attached is a PDF of a display I did 10 years ago using a DG7-32. I think it appeared in the NBTVA newsletter around that time but I'm not sure. Today I might do it in a different manner but as you can see it worked as described.
I've posted this before, so I apologise to those that have already seen it...
That took 30 minutes to upload for such a small file...rebooted PC and modem...no idea why
FlyMario wrote:Yeah it is more about a 16 dollar b/w tv that works having all of the power circuits. In my mind, I can cut the v and h coils and begin developing a good circuit to drive the electron beam in a pattern necessary for NBTV. I think in this case I can avoid all effort in trying to drive the tube itself. It would seem that whatever I do for the TV tube would be somewhat applicable to the Russian tube which is my end goal. Sure there would be different power requirements. That information might not even remotely scale.
I guess I could have just used my Tektronix 2246 instead of buying the little TV. That would have been more practical. LOL. In a bit of a daydream mode.
I do get completely scared of the high voltages. I find myself being very Absent minded. For instance, I can be soldering something, sit down at my desk... stand up and can't find my solder. For some reason, I put it on my desk. Afraid what I might grab that might knock the hell out of me.
FlyMario wrote:oh wait. Are you saying it takes 7kv to deflect the electron beam? Lordy.
Andrew Davie wrote:Just a reminder I have a small collection of CRT tubes basically just for the cost of post and pack.
FlyMario wrote:I am very happy to announce my Russian tube is here!
Hope I don't get accused of colluding with Russia over it!
It's so pretty! Must ... put... it ... back. Have too much stuff to do for Halloween props and my mechanical tv.
Puzzled though, why there is no nipple on top for a flyback (?). I see no place where that would connect.
Anyways... its so cool looking. It must not become a clock face... no... stop thinking about that Pete. NBTV instead.
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