BBC Marconi ribbon microphone, 1934-1959.

The Marconi ribbon microphone was used by the BBC until 1959. The tiny presure changes, caused by the aluminium ribbon which is les than a thousandth of a millimetre thick, vibrate between the poles of a large magnet. These generate currents which mimic the sound wave. A radio microphone is a transducer, which is a device that translates voltages and currents into sounds, lights or forces.