This is an analogue apparatus to illustrate electrical current flow. It consists of a large board on which is mounted a low-voltage electric pump, connected to 4 mm socket terminals, which circulates the water through the 'circuit'. The circuit is of clear plastic tubing connected to glass tubes of different bores representing resistance. Across the 'resistance' is connected a detachable manometer to show the 'potential difference'. Following the resistance is a taper-ended tube discharging into a funnel so that the rate of flow representing the current may be shown.