electrikery wiz question

[tbird]

I Should know the answer to this but confidence low this morning can an electrikery wiz just confirm that the below is basicaly correct, just want to calculate approx input current for 240v to 12v transformer for 12v 7amp continuous load

 

P=EI

so 12Vdc at 7A = 84W

 

P/E =I

so

84w / 220vac = .382A

 

so input current will be iro 382mA plus a bit for ineficiency,heat and rectification

TIA

cheers

 

Tim

 

CSR 200 Aztec and Black

[jackb_ms]

correct

 

 

Emily, The Very Yellow 21

[tbird]

Ta 😶‍🌫️ several years out of bench electronics and the old grey cells start to wonder/wander 😬

 

Tim

 

CSR 200 Aztec and Black

[EFA]

If this is true, your transformer will generate no head whatsoever.

 

Its not 100% efficient.

 

 

^{Full Terms and Conditions} of this post can be read here.

[tbird]

do you mean heat 🤔

thats why I plussed a bit in the final statement for heat and rectification losses

 

Tim

 

CSR 200 Aztec and Black

[EFA]

Teach me to skip read.....

 

 

^{Full Terms and Conditions} of this post can be read here.

[tbird]

Thats usually my trick 😬

 

Edited by - tbird on 22 Nov 2010 23:09:37