It
comprises of a spring mounted on a steel vibrator arm which carries a contact
connected in series with solenoid. The free end of the vibrator carries a
marking point which strikes the paper tape through a disc of carbon paper thus
making the tap once for each oscillation. It works on 6-9 volts, 1 amp A.C.
power supply. The instrument is mounted upon a thick Bakelite base and 4 mm
brass socket terminals are provided for electrical connections. Complete with
one dozen round carbon papers and roll of paper strip along with AC power
supply of 6V to 9V, 1A.