what can i use instead of this cap?

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hi

in this capacitor power supply i use film cap 2.2 uf for input and its large.i want to have small power supply without transformer.

what can i use instead of this c2 cap?it be cool if i can use smd cap in seri or somthing

i want 3.3 v and 200 mA in output and input is 220 AC .

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What is this for ? 

 

It can kill you!!!!!

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Hi.

sorry but it is the life. you must have a capacitor type X2 and it is not small.

and you need to have a resistor serie type carbon composite ( not film) to support the inrush current. 

but if you need small use less current.

Or.

make a 24V dc power from  230Vac like you do and a switch regulator than total current is less, less capacitor and SWregulator take not so much place.

you need 3,3V x 0,2A = 0.66W --> with 24V need only 25mA from 230V ( + - loss i SW regulator) Main capacitor can be about 220nF +-

Thierry

 

Thierry Pottier

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sparrow2 wrote:

What is this for ? 

 

It can kill you!!!!!

thanks cheeky

 

TPE wrote:

Hi.

sorry but it is the life. you must have a capacitor type X2 and it is not small.

and you need to have a resistor serie type carbon composite ( not film) to support the inrush current. 

but if you need small use less current.

Or.

make a 24V dc power from  230Vac like you do and a switch regulator than total current is less, less capacitor and SWregulator take not so much place.

you need 3,3V x 0,2A = 0.66W --> with 24V need only 25mA from 230V ( + - loss i SW regulator) Main capacitor can be about 220nF +-

Thierry

 

thanks ill test it

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The reason for using a X2 rated capacitor is that the metalised paper dielectric is self healing. Since you get a lot of transients on the mains, having a device that won't explode is a 'good thing'. Fairchild have some devices that work by chopping the mains and have an integrated regulator and high voltage mosfet. These might suit your application. Nevertheless, in a mains application, you need to chose your components carefully so they fail without causing a fire.

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Kartman wrote:

The reason for using a X2 rated capacitor is that the metalised paper dielectric is self healing. Since you get a lot of transients on the mains, having a device that won't explode is a 'good thing'. Fairchild have some devices that work by chopping the mains and have an integrated regulator and high voltage mosfet. These might suit your application. Nevertheless, in a mains application, you need to chose your components carefully so they fail without causing a fire.

thanks alot

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The only purpose I can think of is if your V2 has a DC component you want to eliminate.

If you don't know my whole story, keep your mouth shut.

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Jeez Louise, amigo,  get yourself a 'wall wart'.  Any one of the many millions of little black plastic phone chargers that turn mains AC into +5v DC and cost maybe a dollar.  Then add a little 10 cent AMS1117 +3.3V regulator chip.  

 

You don't want to be 'experimenting' with 350V electrical levels just to get +3.3V/200 milliAmps.  Plus all the time that you save by not building this little electric chair can be spent on the Internet learning how power supplies are designed.

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Simonetta wrote:

Jeez Louise, amigo,  get yourself a 'wall wart'.  Any one of the many millions of little black plastic phone chargers that turn mains AC into +5v DC and cost maybe a dollar.  Then add a little 10 cent AMS1117 +3.3V regulator chip.  

 

You don't want to be 'experimenting' with 350V electrical levels just to get +3.3V/200 milliAmps.  Plus all the time that you save by not building this little electric chair can be spent on the Internet learning how power supplies are designed.

Could not agree more with this.

 

If you want to put it in an enclosure yourself:

http://www.ebay.com/itm/220V-to-...

 

 

or the no fuss model:

http://www.ebay.com/itm/NEW-Unii...

 

Jim

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Last Edited: Thu. May 19, 2016 - 01:30 AM
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Where does that ground go? You cant use a full wave rectifier on ac... one leg is ground.

 

Imagecraft compiler user

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Very true.

LTSPICE complains and refuses to simulate if you don't give it a 'ground' reference.