You Do Need power plug adapter while traveling from Armenia to Cameroon.

Here is Why You Need An Adapter

The outlet and plug type used in Cameroon are C and E and in Armenia are C and F. This is how they look like.

Armenia

In Armenia, outlets of type C and F are in use.

Type C

Type F

Cameroon

In Cameroon, outlets of type C and E are in use.

Type C

Type E