You Do Need power plug adapter while traveling from Bangladesh to Bhutan.

Here is Why You Need An Adapter

The outlet and plug type used in Bhutan are C, D and G and in Bangladesh are A, C, D, G and K. This is how they look like.

Bangladesh

In Bangladesh, outlets of type A, C, D, G and K are in use.

Type A

Type C

Type D

Type G

Type K

Bhutan

In Bhutan, outlets of type C, D and G are in use.

Type C

Type D

Type G