Coil about 240 turns No. 28 S.W.G. aluminium wire to suit gap but with tripod broken away, part of Oliver Lodge’s microphone amplifier or relay, 1898 (British patent 9712 of 1898) ), a precursor of the moving-coil loudspeaker Coil about 240 turns No. 28 S.W.G. aluminium wire to suit gap but with tripod broken away Radio Communication
Circular permanent magnet with annular gap 1 3/8" to 1", part of Oliver Lodge’s microphone amplifier or relay, 1898 (British patent 9712 of 1898), a precursor of the moving-coil loudspeaker Circular permanent magnet with annular gap 1 3/8" to 1" Radio Communication
KB Featherlight 11 inch mains portable television set, 1964 KB Featherlight 11 inch mains portable television set Radio Communication 1964