Step 1: Check the laptop charger voltage and current.

check the specs of your Dell laptop charger

Normally you can find these parameters on a label at the bottom of the notebook. For example, the tag shows "Input: 19.5V 3.34A", then the corresponding parameters of the laptop power adapter is "Output: 19.5V 3.34A".

Sometimes there is not a tag at the bottom of your laptop, then you can check the tag of your original laptop charger.

Step 2: Check the laptop charger connector size.

check the connector size of your Dell laptop charger