Ringer. Ringer MC-131 is of the single-gong type. The ringer
coils, armature, and clapper are mounted internally to the gong (figs. 6.
7. 8. and 20). When energized by ringing current, the armature operates
the clapper about a pivot to strike alternately two internal projections of
the gong rim. The acoustical output is high for a relatively low electrical input.
The transmission loss through the ringer, or the ringer and the
capacitor in series, and the holding coil is negligible because of the high
impedance to voice-frequency currents of these elements.