Pole pieces for same magnet altering to annular gap, 1898

Made:
1898

Pole pieces for same magnet altering to annular gap approximately 3 7/8" to 3 5/16", part of Oliver Lodge’s microphone amplifier or relay, 1898 (British patent 9712 of 1898) ), a precursor of the moving-coil loudspeaker

Details

Category:
Radio Communication
Object Number:
1926-713
type:
pole
credit:
Sir Oliver Lodge.