The phones were powered by voice? Wasn’t it just that the amplifiers weren’t very good.
Technically yeah your voice has power because it’s moving air around, but it’s a microscopic amount of energy. If you hold a piece of paper up in front of your mouth and just speak normally it will barely move, even if you yell it hardly goes anywhere. There’s more energy in a calm breeze.
Ex-navy electrician here. They use a microphone transducer to convert sound pressure from your voice into electric current. They convert it back to sound by a transducer at the receiver node. The Navy still uses it because it doesn’t require any outside electricity which is prefect for emergencies.
Fun fact, one of the things we’d do to haze new recruits is to send them to the ICmen to ask for a sound powered telephone battery.
