Figure 9-6.--IC/B3S4 bell.
Figure 9-8.--IC/Z1D4 buzzer.
resonating projections to give the sound a distinctive
frequency characteristic. The resonated horn is
designed in a variety of types, differing as to
intensity, frequency, or power supply. Figure 9-9 is
an illustration of a resonated horn.
Motor-operated horns (types IC/H8D3, IC/H8D4,
and IC/H8S3 use electric motors to actuate the
Figure 9-7.--IC/B2D4 bell.
There are three types of horns used with the
alarm, safety, and warning systems. They are (1)
non-resonated horns, (2) resonated horns, and (3)
Nonresonated horns (types IC/H1D4, IC/H4D2,
and IC/H4D3) use a diaphragm actuated by a
vibrating armature to produce sound of the required
Resonated horns (types IC/H2S4 and IC/H2D4)
Figure 9-9.--Resonated horn.
also use diaphragms and, in addition, have