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# Physics/regulated transformer

Question
QUESTION: hello,
please tell me, if i am using a grounded voltage multiplier as a source of HV DC to create air ions, would the transformer from the wall socket be best as regulated or unregulated. the amperage that will be flowing through the HV circuit is only <70 micro-amps (so almost negligible), but i need it to develop the full voltage (25kV) at the HV terminal. i read how the regulation of the transformer is crucial when the circuit is not under load in order to develop the full voltage as one or the other will not develop the full voltage unless the circuit is under load, but i can not remember which it is; regulated or unregulated. i think it was that the unregulated only supplied the current if there was a circuit but a regulated transformer develops the full voltage without there needing to be a load, is this correct?
thank you,
gene

ANSWER: If you're just looking for maximum ionization, you don't need regulation.  Regulation should limit the current flow to your high voltage end to maintain the voltage.  Unregulated, you might exceed the voltage.

---------- FOLLOW-UP ----------

QUESTION: thank you, because of the way voltage multipliers work, regarding the HV transformer, i am just needing to know if the rated amperage of the wall power adaptors rated apmarage. does it make a difference to the voltage if the unregulated power adaptor has a rating of 4amps or 500 miliamps? the manufacturer recommended the 4 amp rated adaptor but that was for universal usage, i only intend to use it for an air ioniser experiment and need only for the voltage to be the highest at the HV terminal, the amps going through it when it is being used as an air ioniser is only <70 microamps. please tell me, what would the 500 miliamp adaptors maximum output be at the end terminal of a 25kV voltage multiplier so that i can know for further experiments limitation?
thank you,
Gene

Ah, the real question.  Let's do the math.  You need 70 microamps at 25 kV.  That's 1.75 Watts.  You have...you're in Australia, so you should have 230V.  So you should only need 7.6 mA to make that work, power-wise, but for HV transformers you take a huge efficiency hit.  I'm no expert, but I'm guessing you get better than 2% efficiency, so 500 mA should be fine.

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