You Do Need power plug adapter while traveling from Guyana to Switzerland.

Here is Why You Need An Adapter

The outlet and plug type used in Switzerland are C and J and in Guyana are A, B, D and G. This is how they look like.

Guyana

In Guyana, outlets of type A, B, D and G are in use.

Type A

Type B

Type D

Type G

Switzerland

In Switzerland, outlets of type C and J are in use.

Type C

Type J