|This high quality cardboard construction kit allows you to build your own version of the classical high voltage generator - with limited current for safe experiments! For many people this machine is the most vivid memory of their physics classes at school. Everybody is fascinated by the crackling flashes of lightning that appear between the electrodes when the crank on the back is turned. Two counter-rotating acrylic discs with aluminium segments produce static electricity of up to 70,000 volts that is stored in two Leyden jars made from PVC and aluminium foil. The Leyden jars are discharged via two spherical electrodes, producing bright sparks. The capacity of the Leyden jars is deliberately limited, so that the electricity produced is completely harmless.