Page 1 of 1
Question about AC adapter
Posted: Thu Jun 25, 2009 1:31 am
by thinkpac
I have the 93P5026 AC adapter, which has the following specs:
input: 100-240v, 2.4A
output: 20V, 4.5A
The 42T5093 power cord that I have says "3A 125V". Did I get the correct power cord? Shouldn't the power cord have a higher amp rating than what the AC adapter is outputing?
Re: Question about AC adapter
Posted: Thu Jun 25, 2009 2:12 am
by Harryc
The power cord is fine. You're talking apples and oranges ... the Output of the adapter is DC, the power cord is AC.
Re: Question about AC adapter
Posted: Thu Jun 25, 2009 8:15 am
by dr_st
thinkpac wrote:Shouldn't the power cord have a higher amp rating than what the AC adapter is outputing?
Nope, since the power cord is between the wall and the adapter, it should have a higher amp rating than what the adapter is pulling from the wall. Which it does.
Re: Question about AC adapter
Posted: Thu Jun 25, 2009 3:11 pm
by bhtooefr
Actually, AC vs. DC isn't what the rating's about. dr_st answered it, but I'll explain further.
The cord goes between the adapter and the wall. The cord is used in 110-120 V applications, and is rated for 125 V. The adapter will pull a maximum of 2.4 A.
Now, volts times amps equals watts (roughly. Watts and volt-amps are actually somewhat different when dealing with AC, but for our purposes, it's close enough.) That means that the cord is rated for 375 W when at 125 VAC. Which is fine - the most the adapter will ever pull when at 125 VAC is 300 W.
The power adapter is then converting the power to DC and changing the voltage - hence the output amps going up, although it doesn't go up as much as you'd expect, thanks to the conversion losses. 20 V @ 4.5 A = 90 W.