supply without transformer

[mr_byte31]

220v to 9v without transfomer circuit

hi
i want to design a supply without using a transformer
the supply is 220/12
i thought to but a rectifier then a resistor then a zener 9v
what i want to know does the supply can supply much current
and is it stable

 

[Eugen_E]

The output current will be less than 50 - 100mA. In order to reduce power loss, you will use a series capacitor instead of resistor. Be carefull, the suply it's not isolated from the mains.

https://ww1.microchip.com/downloads/en/AppNotes/00954A.pdf

 

[Johnson]

hi
i want to design a supply without using a transformer
the supply is 220/12
i thought to but a rectifier then a resistor then a zener 9v
what i want to know does the supply can supply much current
and is it stable

"a rectifier then a resistor then a zener " will put you in troble and it is not safe. You may harm yourself with elctric shook. I recommend you to use small flyback circuit with TOP224, or 5v is suffecient(?) use mobile phone chargers

 

[flatulent]

There are severe safety problems involved in not using a transformer. I would suggest that if you are not a chartered engineer and know the safety laws, that you should definitely use a transformer.

 

[ehsanelahimirza]

it will work but only to a limited and predefined amount of current

u will use high wattage resistors like for 100mA u need 20watt resistor and almost 1K or above resistance

design is not feasible as a power supply, as it has a lot of loss as compared to load usage

 

[jrguy8]

any has a schematic of 110V-220V input to 5V 1A output just like in those charger using simple smps? i wonder why most fake chargers can't charge my cellphone but original does.
is it possible to adjust current output of a 5V 400ma rated charger to 1A?