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Votage doubler safety
Votage doubler safety
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Old 15th September 2020, 07:34 PM   #1
Palustris is offline Palustris  United States
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Default Votage doubler safety

Is it safe to use a voltage doubler on one secondary of a power transformer if the other secondary is a high voltage full wave referenced to ground?
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Old 15th September 2020, 08:51 PM   #2
rayma is online now rayma  United States
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Yes, that will be ok in this case.
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Old 15th September 2020, 09:04 PM   #3
Palustris is offline Palustris  United States
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Thanks Rayma!
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Old 15th September 2020, 09:10 PM   #4
rayma is online now rayma  United States
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What amplifier is that?
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Old 15th September 2020, 09:20 PM   #5
JMFahey is offline JMFahey  Argentina
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Quote:
Originally Posted by Palustris View Post
Is it safe to use a voltage doubler on one secondary of a power transformer if the other secondary is a high voltage full wave referenced to ground?
Sorry but that schematic is wrong.
Transformer tap #6 will be shorted to ground on negative semicycles.
And tap #8 is shorted to ground all the time through the bottom 470uF capacitor.
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Last edited by JMFahey; 15th September 2020 at 09:22 PM.
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Old 15th September 2020, 09:42 PM   #6
rayma is online now rayma  United States
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That looks to be true. Is this out of a commercial product, or just a schematic?
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Old 16th September 2020, 02:08 AM   #7
dgta is offline dgta  United States
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Wait just a second.

Quote:
Originally Posted by Palustris View Post
Is it safe to use a voltage doubler on one secondary of a power transformer if the other secondary is a high voltage full wave referenced to ground?
The answer to that question is yes. But that's not what you have. You don't have "one secondary" and the "other secondary". You have one secondary with multiple taps. That's a different kettle of fish. You need to make sure it's properly designed and wired. As said, you have a short in there.

Make sure it's all correct and run a sim if in doubt. Otherwise things can go boom ouch.
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Old 16th September 2020, 02:19 AM   #8
Palustris is offline Palustris  United States
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This is a PP pentode connected 807 5-20 inspired amplifier I am building from my own schematic. I was hoping to get 300V for a screen supply off of the other secondary tap. I was pretty certain it was incorrect which is why I asked for help.
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Old 16th September 2020, 02:26 AM   #9
audiowize is offline audiowize  United States
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You could try hooking those taps up to a couple of UF4007 diodes with a small choke input filter to crank the voltage down. Screen current is pretty minimal, so this may indeed be a reasonable option.
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Old 16th September 2020, 02:27 AM   #10
TonyTecson is offline TonyTecson  Philippines
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you can learn it the hard way, or you can use caps to isolate your voltage doublers input voltages...
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