How do i convert 220v to 12v without a transformer

nelson64 over 2 years ago

I am trying to build a circuit with a transformer to put in 220v to get 12v and if possible get 5v out to

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scottiebabe over 2 years ago in reply to michaelkellett +3

Yes.. Perhaps E14 produce a learning module on clairvoyance so we can all do better
michaelkellett over 2 years ago in reply to Jan Cumps +2

It's a Schrödinger Transformer. MK
Jan Cumps over 2 years ago +2

The most used method is to use a capacitive dropper. It can reduce the mains to a manageable voltage with little loss, You need to know the impedance of your load to calculate the capacitive dropper's…

Jan Cumps over 2 years ago

With or without? Title says without, text says with.
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michaelkellett over 2 years ago in reply to Jan Cumps

It's a Schrödinger Transformer.

MK
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nelson64 over 2 years ago in reply to Jan Cumps

without
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michaelkellett over 2 years ago

Do you need isolation ?

Some mains powered devices do not need isolation in an internal low voltage power supply. Unless you are very confident that the whole system will be safe you should use a transformer.

What is your 12V for, how much power, AC or DC etc.

MK
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Jan Cumps over 2 years ago

The most used method is to use a capacitive dropper. It can reduce the mains to a manageable voltage with little loss, You need to know the impedance of your load to calculate the capacitive dropper's value.

You didn't specify if it's 12 V DC or AC. If it's AC, you can just have that dropper. If it's DC, you will have to additionally rectify that voltage. You can then further try to stabilise that voltage if you need.

Your project will not be isolated from the mains voltage. This is all very dangerous. Only to be done if you know what you are doing, and if there is no way for anyone to touch anything.

en.wikipedia.org/.../Capacitive_power_supply
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colporteur over 2 years ago

Using the experience of the E14 Community to troubleshoot a power supply

I repaired a commercial residential door bell that had a circuit to reduce 120VAC to 12V. It was the first time I had seen such a circuit. The link provides the details. I found it scary to work on PCB's with no isolation. IT has been a while since I worked in the vacuum tube environment. 3V & 5V is mostly what I see now.
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dougw over 2 years ago

I've seen this done with capacitive dividers in motor controllers for small amounts of low voltage current.
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scottiebabe over 2 years ago

I would just use a transformer its simple, easy, and it just works. If need be, you can still reference the secondary to live or neutral, etc, etc...
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Jan Cumps over 2 years ago in reply to scottiebabe

always.
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nelson64 over 2 years ago in reply to michaelkellett

It is to run a water pump of 12v dc and timer that use 5v
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