On This Day in Telephone History April 14TH 1877 Emile Berliner filed a Variable-Pressure Transmitter Caveat.
Berliner discovered that the minute atmospheric vibrations due to sound waves would cause a diaphragm to vibrate, which vibrations, by varying the pressure between the point of contact between metallic electrodes, in constant contact, produced variations of electrical resistance whereby speech may be transmitted.
🛠 Think Like a Telephone Engineer
Every breakthrough in telephone history began with an engineer solving a problem. Could you solve it?