Choosing the right AC/DC adapter Before you buy any AC/DC laptop adapter, please make sure the AC/DC laptop adapter will give you the correct voltage and suitable current output. To find out the voltage & current, turn your laptop over and look for a label, sticker or writing which shows the voltage and current, it should look something like the examples below. The voltage figure will have a “V” after the Number i.e 19V and the current will have a “A” or “mA”. i.e 3.15A, 950mA. You can also find these shown in a similar fashion on the original AC adapter if you have it. In the examples below the voltage & current has been marked with a red ring. Enter the voltage and current then click calculate for the wattage Enter Voltage V Enter Current A : If the wattage requirement for your laptop is lower than the 60W or 90W output of the adapter, it will not damage your laptop, your laptop will only take the amount of power it requires. I.E. If your laptop needs 45W, then either the 60W or 90W will work OK. If your laptop needs 80W then you will need the 90W one as the 75W one will not be powerful enough. Only if you were to plug a 19V adapter into a 15V laptop would you run the risk of damage. If in doubt please email us on our contacts page. TOP Information for AC laptop adapter. AC Power Adapter can provide continuous power to your laptop/notebook computer and charge the laptop battery from AC power source such as electrical plugs ………