How to convert voltage requirements to watts?

[axemanxt40]

My DVD drive says it needs this for voltage...but it gives no amps! So how do I convert this to watts?

"+5V +/-5% and less than 100 mVp-p ripple voltage

+12V +/-5% and less than 200 mVp-p ripple voltage"

 

[Viper GTS]

You don't have enough information.

Viper GTS

 

[GTiBri]

Watt = Volts * Amps

(If my brain is working right today that is...)

 

[OverVolt]

need resistance too... i think theres 2 diff simple equations

 

[shenaniganz]

Originally posted by: GTiBri
Watt = Volts * Amps

(If my brain is working right today that is...)

Actually isn't it P=I^2*R so it would be Watt = Volts * Amps^2

(my brain might not be working right today either tho...)

 

[nineball9]

As Viper GTS noted, you need more info, axeman.

For DC, Ohm's laws:

E=IR
P=EI

 

[Woodchuck2000]

Originally posted by: shenaniganz

Originally posted by: GTiBri
Watt = Volts * Amps

(If my brain is working right today that is...)

Actually isn't it P=I^2*R so it would be Watt = Volts * Amps^2

(my brain might not be working right today either tho...)

Basic physics dudes, both are correct...

DVD drives typically consume between 10-30W, depending on how fast it's spinning and the exact model.

 

[aka1nas]

Originally posted by: shenaniganz

Originally posted by: GTiBri
Watt = Volts * Amps

(If my brain is working right today that is...)

Actually isn't it P=I^2*R so it would be Watt = Volts * Amps^2

(my brain might not be working right today either tho...)

P=I^2 *R, but V=I*R, so P=I*V or Amps*Volts

 

[sharkeeper]

Nowhere does your text indicate you need to know the power consumption typically measured in Watts.

+/- 5% is typical (allowed) variances in computer power supplies. The ripple voltage is indicative of remnants of AC and/or spurious harmonic artifacts from switching power conversion. Good power supplies typically will have less than 50 mV peak to peak ripple. Too much ripple can cause problems in circuits performing pulse code modulation operations even with good implementation of Cross Interleave Reed-Solomon Code.

Cheers!