psu that can supply 200ma with two tap 250vdc and 136

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skal1
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#1 psu that can supply 200ma with two tap 250vdc and 136

Post by skal1 »

Hi lads,

Need some help with a psu , i have only built some some dual voltage stuff so this high voltage psu will be a challenge for me OK

i have built a psu already the supply after diode 1n4007 rectification and smoothing caps 200uf 400 volts is 414vdc, i need two taps, 250vdc and 136 , i think i will have to build a voltage divider to get the two taps i want.

not sure so any help would be nice.

thanks

skal1
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pre65
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#2

Post by pre65 »

Try this calculator from the Electronics 2000 web site.

http://www.electronics2000.co.uk/calc/p ... ulator.php

That web site is superb for calculations relating to our hobby.
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Nick
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#3

Post by Nick »

What current do you need from the two taps, and what is it for.
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#4

Post by skal1 »

hi nick ,

just go the info of a friend , amp stage 250vdc tap needs current for 4x5687 and the 136vdc tap need to provide current for 4x6bc8 .

Can i work out the current need from this info or is my info needed

Thanks again

skal
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#5

Post by Andrew »

A voltage tap using a potential divider can't supply, they are only good for a voltage reference, so, you might want to consider regulation (quite complicated at higher voltages but a technically superior solution) or simple voltage dropping using a resistor cap resistor combo.

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Nick
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#6

Post by Nick »

skal1 wrote:hi nick ,

just go the info of a friend , amp stage 250vdc tap needs current for 4x5687 and the 136vdc tap need to provide current for 4x6bc8 .

Can i work out the current need from this info or is my info needed

Thanks again

skal
Are you sure you mean 5687? What is the circuit going to be doing?
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skal1
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#7

Post by skal1 »

Hi

sorry for the last post i think i was half a sleep when i wrote that :D , anyway
2x5687 are for driving amp for detector stage i believe and 2x6cb8 is make input / make gain , yes it is another compressor.

i am have a problem with the psu so i want to build another .


cheers

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Mike H
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#8

Post by Mike H »

If it's simply a case of dropping supply Voltage surely it's just a dropper resistor to take the Volts out then a filter cap to ground :?:


 
 
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skal1
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#9

Post by skal1 »

Mike H wrote:If it's simply a case of dropping supply Voltage surely it's just a dropper resistor to take the Volts out then a filter cap to ground :?:


but dont you have to know the current drawn by the amp, to calculate the resistor for the voltage drop.


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pre65
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#10

Post by pre65 »

skal1 wrote: but dont you have to know the current drawn by the amp, to calculate the resistor for the voltage drop.


skal1
Yes ! Using the voltage dropped and the current will give you the resistance.

Ohms law ! R = V/I or use this calculator

http://www.electronics2000.co.uk/calc/o ... ulator.php
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skal1
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#11

Post by skal1 »

pre65 wrote:
skal1 wrote: but dont you have to know the current drawn by the amp, to calculate the resistor for the voltage drop.


skal1
Yes ! Using the voltage dropped and the current will give you the resistance.

Ohms law ! R = V/I or use this calculator

http://www.electronics2000.co.uk/calc/o ... ulator.php

ok hmm , i do not know the current drawn by the amp , so what do i do now?

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#12

Post by pre65 »

skal1 wrote:
ok hmm , i do not know the current drawn by the amp , so what do i do now?

skla1
Are you working to an existing circuit, if so can you post the circuit diagram ?..

If it's a new design can you post a drawing of what you have in mind please ?
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#13

Post by Mike H »

Welcome to the world of trying to make electricity do what you want and not letting it do what it wants, lol :lol:


 
 
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pre65
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#14

Post by pre65 »

Use the data sheets from this site to work out what current each valve will take.

http://tdsl.duncanamps.com/index.php

I probably know less than you do but at the voltages you have suggested it would seem 8ma on each anode would be about right. (waits to be shot down by anyone clever :wink: )

PS what about the anode load resistor ?
The only thing necessary for the triumph of evil is for good men to do nothing.

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skal1
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#15

Post by skal1 »

sorry can not post circuit not my property, this is the reason i want to design my own psu.

, ok found the 5687 data so how do i work out the current draw of 1 5687 at 250vdc.


skal1
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