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Author Topic: 9v or 12v from PSU? (Read 4823 times)

Offline John Fante

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9v or 12v from PSU?
« on: 2022.January.11. 12:00:13 »
This maybe a dumb question but should the standard PSU output 9v og 12v and does it make any difference?

On my PSU it says that it outputs 9v but when I measure it really outputs 12v :?: (no load)

I have tried with a new high quality 9v PSU and the computer works fine with 9v.

This is rather old equipment and I do not want to strain things.

Offline Tuby128

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Re: 9v or 12v from PSU?
« Reply #1 on: 2022.January.11. 12:25:54 »
Can you show me a picture about your power supply?

Offline Zozosoft

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Re: 9v or 12v from PSU?
« Reply #2 on: 2022.January.11. 12:35:07 »
Yes, it is normal, without load will be higher voltage on old PSU. With load need to be 9V (German PSU) or 9.5V (UK PSU).

Offline John Fante

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Re: 9v or 12v from PSU?
« Reply #3 on: 2022.January.11. 12:45:16 »
Aha. Thank you for the reply! :)

Just in case (@Tuby128). Here is a picture of the PSU:

https://www.dropbox.com/s/c3tp0s5xf4dvdef/PSU.jpeg?dl=0

And here is a picture of the reading:

https://www.dropbox.com/s/n8nuyccmn3xa8lx/Measurement.jpeg?dl=0



Offline Tuby128

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Re: 9v or 12v from PSU?
« Reply #4 on: 2022.January.11. 12:58:16 »
Ok you were talking about the old supply, not a new one, i see.
The circuit has a capacitor inside, without load (EP) the voltage goes to the peak value which is 12V. After you connect the load (EP) the voltage will be sink to 9V level.

Offline John Fante

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Re: 9v or 12v from PSU?
« Reply #5 on: 2022.January.11. 14:12:21 »
@Tuby128

Aha. Great to know :)