Why does a HD take less Amps on 5V than on 12V?

[elpres05]

My seagate HD writes,

5V -------- 0.63 A
12V ------- 0.74 A

That means around 4 watts on 5 Volts and 8 Watts on 12 V.

Using power= I x V, doesnt the 5V line require more amperes to compensate the overal power consumption?

Or does the HD RPM decrease on 5V. I actually want to use my hard drive solely on 5 Volt, is it possible?

 

[Bassyhead]

The 5V and 12V voltages are used for different things. Most drives, be it hard drives or optical, use the 5V line for the circuitry of the drive and the 12V line for the motors. If you wanted to run the drive solely off 5V, you would either need a DC-DC convertor to obtain 12V from the 5V or use a laptop hard drive, which I think only need 5V.

 

[elpres05]

Originally posted by: Bassyhead
The 5V and 12V voltages are used for different things. Most drives, be it hard drives or optical, use the 5V line for the circuitry of the drive and the 12V line for the motors. If you wanted to run the drive solely off 5V, you would either need a DC-DC convertor to obtain 12V from the 5V or use a laptop hard drive, which I think only need 5V.

Well actually thank you, i was wondering why ppl say HD power consumption nearing 15 Watts. You explaination also says that.

 

[techs]

Originally posted by: Bassyhead
The 5V and 12V voltages are used for different things. Most drives, be it hard drives or optical, use the 5V line for the circuitry of the drive and the 12V line for the motors. If you wanted to run the drive solely off 5V, you would either need a DC-DC convertor to obtain 12V from the 5V or use a laptop hard drive, which I think only need 5V.

Which also explains why my external notebook hard drive can run from the usb bus power of 5v.

 

[elpres05]

Originally posted by: techs

Originally posted by: Bassyhead
The 5V and 12V voltages are used for different things. Most drives, be it hard drives or optical, use the 5V line for the circuitry of the drive and the 12V line for the motors. If you wanted to run the drive solely off 5V, you would either need a DC-DC convertor to obtain 12V from the 5V or use a laptop hard drive, which I think only need 5V.

Which also explains why my external notebook hard drive can run from the usb bus power of 5v.

Does anyone know a laptop raptor ?