Operates on 12V a.c The timer employs electromagmet, with
spring loaded armature which vibrates above a support table
for a carbon paper disc. Paper tape, drawn through guides
on the table, is struck by a dotting screw carried on the
armature, Additional with extra guides accommodate 4.5 mm
external diameter rubber tubing for the 'Pearls in air' water
drop experiment. The peg on the support table is movable to
allow maximum wus of carbon paper discs.
The ticker tape timer produces dots spaced at 1/50 or 1/60s
intervals depending on main frequency.