How can I connect my modem power supply to the molex connector?

[ajaybc]

How can I connect the modem to the molex connector of my PC(the one that supplies power to the drives?

 

[dOm1naTOr]

@ajaybc
why shud nyone wants to do that?

 

[infra_red_dude]

You cannot do that widout a regulation circuit which is not easy to build.

 

[ajaybc]

Ok I just to do that to switch off my modem wen my PC is off

 

[sashijoseph]

Connect the modem's adaptor to it's 220v supply through a relay driven by the 12v from the molex.This way the modem switches on and off with the pc.

 

[infra_red_dude]

^^^ Thats a nice simple switch for which he'll hafta cut thru the wires of his modem adaptor.

 

[dOm1naTOr]

Just an idea. dun try it
get the negative for da adapter from the cabby.

 

[sashijoseph]

Thats a nice simple switch for which he'll hafta cut thru the wires of his modem adaptor.

No need to cut through any wire.Have a look at the attached (crude) schematic.

 

[infra_red_dude]

^^^ Yep, nice and simple circuit, sashi

 

[dOm1naTOr]

@sashijoseph
u a mallu?

 

[sashijoseph]

^^No brother.......but it seems Digit is doing good business in Kerala;we have a Mallu in almost every thread.

 

[zyberboy]

u can directly connect the 12v output frm molex connector directly to the modem without adapter if ur modem is 12v, no need of regulation

 

[infra_red_dude]

^^^ No you can't most of the adaptors are 7.5-9V, ~1A. Even if the modem has as 12V DC input the current will hafta be regulated.

 

[zyberboy]

^^if the modem is having 12v adapter he can take 12v output frm the molex(yellow is 12+ve and black gnd)
Since modem only uses 1A wer the output of smps is 15A which is much more than the required rating modem will only draw the current it needs which 800ma for ut-300r2u
But To be safe connect 10 ohm 5/10 watts wire wound resister in series with yellow +12v to limit the Ampere to 1.2A