A traditional device capable of generating high electrostatic potential that can produce spark of length up to 7.5cm under favourable weather condition.
Equipped with two clear acrylic plates, each of diameter about 25cm and having aluminium sectors permanently pasted radially along the rim. Both the plates mounted parallel to each other and rotate in opposite direction through a belt-pulley arrangement. Pulley on one wheel has handle for manual rotation. A set of charge collecting combs in mounted toward either end of a horizontal insulating beam, together with the adjustable spark gap arms, the latter equipped with small metallic sphere discharger at one end and long insulating handle adjustment at the other end.

The charge can be stored in a pair of high capacity Leyden jar capacitors that can be connected or disconnected as desired. When connected to the Leyden jars through a pair of levers, the spherical dischargers starts accumulating the charge and transfer of charge from one discharger to other takes place in the form electric spark jumping from one sphere to other as a consequence of build-up of sufficiently high potential difference across the two spheres. The spark produced intermittently by the continuously rotating plates. Complete apparatus is mounted on a well insulated base that also carries a pair of earth terminals for the Leyden jars.