Alexander Graham Bell’s big breakthrough came on 10 March 1876 when he used what he called a ‘liquid transmitter’. This was a vertical metal cone with a piece of parchment stretched like a drum over its narrow end at the base. ...... view full post here ----[https://www.naijacampusblog.com/2020/09/how-did-first-phone-call-work-study-hub.html]