Is there an inbuilt voltage doubler/tripler in Modern half-wave DC DST flyback or just a inbuilt diode?

Hi, I have dc half wave modern type DST flyback from a   computer  CRT and put out around 30kv. I wonder: Is there an inbuilt voltage doubler/tripler in  these modern half-wave DC DST flyback or just a inbuilt diode?  I became every confused from very contradiction   info.   Why I ask? I want to know as well as I would want to build a multiplier for the flyback.   I know mine isn't the old AC type but the DST should be a DC  pulsed ...The  flyback I have just  looks like these typoical modern DST ones here: http://www.imagebam.com/image/b88cbf268367234 . Your help would be tremendously relieving for me. I have been struggling to  find out  for a while now...  Thanks a lot

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It's just a flyback transformer. There are no other components built in. But the transformer needs a driver circuit to feed it the AC voltage it needs to operate. SO look for driver schematics that give you the desired output from the desired input.
leviterande (author)  mpilchfamily3 years ago
Thanx for the reply!, yes I have many different drivers for the transformer. that is no problem. You said "There are no other components built in" I believe you are mistaken, this Dc transformer has at least a diode inside to rectify the Ac, all modern type flyback got a rectifier inside. What I am not sure though is whether the Flyback got a tripler/doubler as well as some people say that hmmm, its near impossible to find that out without tearing it up

Sorry about the necromancy, but a Google search got me here, so I'll chip in for accuracy's sake:

You are correct, leviterande, that mpilchfamily is mistaken. While AC-only, component-free flyback transformers DO exist, they are not what anybody is likely to find and refer to as a "flyback transformer," these days.

As for your question, I've never heard of built-in voltage multipliers, but that doesn't mean much. :-) That IS a topography used for other types of high-voltage sources, like those found in ion-generators, AND many flyback transformers seem to contain the right sort of components (diodes, capacitors) onboard... but I am guessing that's not what those are there for. I think that the cathode-ray tubes these were meant to excite, take a threshold voltage level to turn on, and then some minimum amount of current to control. Given the losses inherent in each stage of a voltage multiplier, and the achievability of threshold voltages using flyback inductive effects alone, I'd expect there is little reason to add multipliers to an FBT from any CRT device.

No doubler/ tripler only diode.
If its got a doubler, you won't have DC continuity from the output pin to the ground.
leviterande (author)  steveastrouk3 years ago
Thanks Steve, I am a little confused from the different answers, I just measured continuity from the HV outputs coming from secondary. Zero continuity. The resistance was also above scale.
Measure it the other way round.
leviterande (author)  steveastrouk3 years ago
I did and still got zero continuity and seemingly infinite resistance...
Try a real voltage source. The resistance is BOUND to be VERY high though
leviterande (author)  steveastrouk3 years ago
Ok, I have connected my 24v PSU as shown here: https://www.instructables.com/id/How-to-find-the-primary-and-the-secondary-coils-of/
I Got a reading of only 3.6V instead of the "should be" 5V minimum but that's maybe alright?.
Anyway I recorded the waveform of this CRT DC flyback and what I got looked like damped AC oscillations ha?
http://www.imagebam.com/image/b35481269380401 (Ignore the freq and volt reading as the numbers were fluctuating a lot).
I measured by first having both my flyback´s 0V pin and the oscilloscope probe-ground grounded. The probe itself is 1ft away from the flybacks positive sphere terminal. I am finding this very strange that the wave looks like AC and nothing like pulsed DC... as if there was no diode inside, I am a beginner so I must have been missing something vital here . Thanks a lot for you time.
leviterande (author)  The MadScientist3 years ago
Thanks a lot. Do you know this for sure if I may ask? have you torn up a flyback and looked inside it? Regards