Original 45W Acer...
For the model A13-045N2A, the power jack(The plug fits into the laptop) has two different sizes:
1. Internal Diameter: 1.7mm External, Diameter: 5.5mm
2.Internal Diameter: 1.0mm, External Diameter: 3.0mm
Could you please use a ruler to measure the power jack of your original adapter (Or the power port of the laptop, if your original adapter is lost.)?
If you have no ruler please provide the detailed Model Number of your Acer Laptop.