oscillograph
oscillograph , noun
1.
a device for making a record of the wave forms of fluctuating.
Oscillograph , noun
[Latin oscillare to swing + -graph.]
(Electricity) An apparatus for recording or indicating alternating-current wave forms or other electrical oscillations, especially of voltages or currents; it usually consists of a galvanometer with strong field, in which the mass of the moving part is very small and frequency of vibration very high.