My old/new laptop adapter specs as given below. I understand the output current for new is 4.5A which is OK when compared to old which provides 3.25A load since it can provide more load.

However, just cant seem to find any idea about input Ampere i.e 1.2A max vs 1.5A(1.5A) I am left with below questions.

  • Does max in 1.2Amax mean anything.
  • does the bracket (1,5A) mean anything.
  • is the new adpater usable inplace of the old

    NEW -
    90W 20V
    AC INPUT 100-240VAC 1.2A max
    DC OUPUT 20V / 4.5A
    OLD -
    65W 20V
    AC INPUT 100-240VAC 1.5A(1,5A)
    DC OUPUT 20V / 3.25A(3,25A)

I think one of the questions regarding brackets probably might just be dot vs comma notation

  • \$\begingroup\$ Make sure to read existing questions before you ask. \$\endgroup\$ Dec 17 '15 at 9:19
  • \$\begingroup\$ had a fair idea on output current. my questions were for input current and what they meant. \$\endgroup\$ Dec 17 '15 at 10:21

It probably means the new device is power factor corrected - it says it will not take more than 1.2 A and this compares favourably with the previous device that says it can take up to 1.5 A.

The previous device might not have PF correction circuits although this is a little speculative to say so.

  • \$\begingroup\$ so can i use to new adapter instead of old \$\endgroup\$ Dec 17 '15 at 8:45
  • 1
    \$\begingroup\$ Yes you can do that. \$\endgroup\$
    – Andy aka
    Dec 17 '15 at 8:48
  • \$\begingroup\$ does input current here mean - the current drawn by the device when there is no power being drawn from the output? \$\endgroup\$ Dec 17 '15 at 8:51
  • 1
    \$\begingroup\$ No it's the maximum input current taken by the device under full load conditions (usually) and, for a modern switch mode device this will occur at the lowest input voltage. \$\endgroup\$
    – Andy aka
    Dec 17 '15 at 8:52

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