You Do Need power plug adapter while traveling from Congo to Ethiopia.

Here is Why You Need An Adapter

The outlet and plug type used in Ethiopia are C, F and G and in Congo are C, D and E. This is how they look like.

Congo

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

Type C

Type D

Type E

Ethiopia

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

Type C

Type F

Type G