150W 7.7A 19.5V How to choose AC adapter replacement HP HSTNN-CA27 646212-001 645509-002 for charger?Hp ProBook 6540b 6545b 6550b 6555b 2140 5101

If you accidentally broke the  HP HSTNN-CA27 AC Adapter. How do you safely buy the right HP replacement adapter ?
There are some points that you need to know. After know about these point, you will avoid buying the wrong adapter.

•  You need know your HP laptop's model number

The laptop number is the unique number which is located on the bottom or on the side of the HP laptop computer. You can also check the user manual or search the computers built- in help program for the model number.The laptop's system's properties will have the laptop model number.

• You need to find HP HSTNN-CA27 adapter wattage requirements

After find your HP laptop model number,you also need to find out the voltage requirement for the concerned adapter. HP HSTNN-CA27 Adapters have different voltage outputs and using the wrong HP laptop adapter can damage one's computer.
Check the user manual for voltage requirements for the HP laptop. The output voltage is normally listed as s DC voltage. Consumers can also check the product or part numbers for the HP laptop model.

• Find a compatible HP HSTNN-CA27 laptop adapter
  You should look for compatibility lists in descriptions of HP HSTNN-CA27 laptop adapters. Laptop model numbers often look similar, so make sure the model numbers match exactly.