In SPICE, voltage sources are often used as ``current meters'', as the current through a voltage source is saved with the simulation result vectors, and can be plotted or printed. The vp device is actually a voltage source (identical to a vsrc device) however the symbol size is tiny, so that it can be more easily added to an existing schematic for use as a current meter. The symbol contains a hot spot in the representation that accesses a branch property that returns a hypertext link to the current vector when clicked on.