The damping system must be used to dampen reflections at
the free end of the oscillating system. To do this, the attenua-
tion bath is placed beneath the last oscillator and filled with
water.
A light stop is attached to the oscillator whose frequency is to
be measured. To measure the frequency, the light barrier with
digital counter should be arranged such that its optical path is
crossed by the light stop at each zero assage of the oscillator.
The digital counter is working as a pulse counter. For a parti-
cular number of pulses the measuring time At is determined
with the stopwatch.