An electrical device includes a circuit board (101), a light source (104), and a light guide (105). The light guide receives light from the light source and conducts the received light to an end of the light guide so that the light crosses, in a direction parallel with the circuit board, an edge of the circuit board. The end of the light guide constitutes a display surface for showing the light to a user. On a fringe area extending from the edge of the circuit board a distance (D) towards the opposite edge of the circuit board, the light guide is between geometrical planes parallel and coinciding with surfaces of the circuit board. Hence, the light guide does not require room in directions perpendicular to the circuit board. Therefore, for example, more connectors, key buttons, and/or other instruments can be placed on a control panel of the electrical device.