Telegraph Sounder Magnets

Clark, James J. · 1865

Telegraph sounders convert electrical pulses into audible sounds and are used to receive Morse code messages. The message travels as a series of electrical pulses through a wire. Short pulses make a dot, slightly longer pulses make a dash. The sequence of dots and dashes represent letters and numbers. The pulses energize the sounder’s electromagnets which move a lever-arm. The arm makes a loud “click” when it strikes a crossbar and the operator translates the pattern of sounds into the original language. This is a patent model for an early form of sound amplifier. The patent covers the addition of a rod attached to the anvil on the electromagnet and connected to the ends of the wooden box. When the lever strikes the anvil, the vibration is also transmitted through the rod to the box boosting the sound.