The ornamental design for “external power source for small electrical appliances, such as mobile phones and tablet computers”, as shown and described.
FIG. 1 is a perspective view of the “external power source for small electrical appliances, such as mobile phones and tablet computers”, showing the new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a top plan view thereof;
FIG. 5 is a bottom plan view thereof; and,
FIG. 6 is a right side elevational view thereof, the left side being the same as the right side.
The broken lines showing LED elements in FIGS. 1, 2 and 5 are included for the purpose of illustrating environmental structure and form no part of the claimed design.