step down transformer help

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power--man

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hi guys

i need sum help

does anyone know if i can get a stepdown down transformer to drop 230Vac(mains) to 12Vac ? and is it expensive

thanks
 

Hi,

230V - 12V transformers are easily available in the market. What is the power rating which you are looking at...the price depends on the power rating...
 
thank you devura i will look in2 it

---------- Post added at 13:24 ---------- Previous post was at 13:11 ----------

im designing a voltage sensor by stepping down the mains voltage to 12Vac , then bringing that voltage down with the use of resistors to 660mv to run a mcp3909, what power rated transformer do u suggest i use?

thank you for all your help
 



Can You give us whole and complete ilustration of problem and final goal ?
Are you plan to make 3-phase energy meter circuit ?

There is tons and tons trafo 220V/110V to 12V, if you cant find just search trafo for halogen light (12V).
 

hi tpetar

Its a single phase energy meter, to sense voltage and current and then send that data to the mcp3909
 

Hi,

I think, a 5VA Transformer should do for your application...
 

This is goal ? You need 9V DC for that.

MCP3909 and PIC18F85J90 Single Phase Energy Meter

**broken link removed**

 

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  • 51884a.pdf
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thanks for the reply

the mcp3909 requires a maximum AC input of 660mv , why would I need a 9V DC ? , im stepping down mains 230V ac to 12V ac , then using resistors to drop it down to 660mv ac into the mcp3909, will it work?

thanks
 

You didnt answer on question in my post #7.

I think You mix current transformer with standard. You didnt make Your question nicely :
does anyone know if i can get a stepdown down transformer to drop 230Vac(mains) to 12Vac ? and is it expensive
Click to expand...


MCP3909 have :
Vdd 7V
Digital inputs and outputs w.r.t. AGND....... -0.6V to VDD +0.6V
Analog input w.r.t. AGND..................................... ....-6V to +6V
VREF input w.r.t. AGND.............................. -0.6V to VDD +0.6V
 

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  • MCP3909.pdf
    1,006.5 KB · Views: 52
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