P
Philip Pemberton
- Jan 1, 1970
- 0
Hi,
Having spent a few days playing around with Ohm's Law and splitting apart
and rebuilding the focus chain for my DG7-32 CRT, I've managed to finally get
a decent spot on the tube face. For those who don't know, the DG7-32 is a 7cm
round oscilloscope CRT with electrostatic deflection.
Now I'm having a problem with the deflection circuitry. Initially I used
the "OZ2CPU" deflection amp design from
<http://webx.dk/oz2cpu/clock-scope/scope.htm>. I've had a few problems with
that - not least of all its strange input signal requirements and the need
for a 400V deflection power supply. Can anyone tell me how to calculate the
gain of the circuit, or maybe even if there is a specific name for that style
of amplifier (so I can go looking for the info myself)?
I also found a similar circuit in Sascha Ittner's CRT clock project. When I
say "similar" I mean "same circuit, different resistor values, +250V HT
instead of +400V and +12V LT instead of +5V".
What I want to build is a deflection amplifier that will take a max. 2.5V
input. If the input is 0V, then the spot is deflected full left, 1.25V
centers the spot, and 2.5V moves the spot to the far right. Ideally I'd also
like to be able to tweak the X and Y gain (=size) and offset (=position).
I've got +240V available from the anode circuit; adding an additional +400V
PSU would involve adding another voltage doubler, and the one that's on there
now isn't exactly small.
Thanks.
--
Phil. | Acorn RiscPC600 SA220 64MB+6GB 100baseT
[email protected] | Athlon64 3200+ A8VDeluxe R2 512MB+100GB
http://www.philpem.me.uk/ | Panasonic CF-25 Mk.2 Toughbook
No software patents! <http://www.eff.org/> / <http://www.ffii.org/>
Wanted: Heisenberg. Reason uncertain.
Having spent a few days playing around with Ohm's Law and splitting apart
and rebuilding the focus chain for my DG7-32 CRT, I've managed to finally get
a decent spot on the tube face. For those who don't know, the DG7-32 is a 7cm
round oscilloscope CRT with electrostatic deflection.
Now I'm having a problem with the deflection circuitry. Initially I used
the "OZ2CPU" deflection amp design from
<http://webx.dk/oz2cpu/clock-scope/scope.htm>. I've had a few problems with
that - not least of all its strange input signal requirements and the need
for a 400V deflection power supply. Can anyone tell me how to calculate the
gain of the circuit, or maybe even if there is a specific name for that style
of amplifier (so I can go looking for the info myself)?
I also found a similar circuit in Sascha Ittner's CRT clock project. When I
say "similar" I mean "same circuit, different resistor values, +250V HT
instead of +400V and +12V LT instead of +5V".
What I want to build is a deflection amplifier that will take a max. 2.5V
input. If the input is 0V, then the spot is deflected full left, 1.25V
centers the spot, and 2.5V moves the spot to the far right. Ideally I'd also
like to be able to tweak the X and Y gain (=size) and offset (=position).
I've got +240V available from the anode circuit; adding an additional +400V
PSU would involve adding another voltage doubler, and the one that's on there
now isn't exactly small.
Thanks.
--
Phil. | Acorn RiscPC600 SA220 64MB+6GB 100baseT
[email protected] | Athlon64 3200+ A8VDeluxe R2 512MB+100GB
http://www.philpem.me.uk/ | Panasonic CF-25 Mk.2 Toughbook
No software patents! <http://www.eff.org/> / <http://www.ffii.org/>
Wanted: Heisenberg. Reason uncertain.