Circular permanent magnet with annular gap 1 3/8" to 1"
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
Details
- Category:
- Radio Communication
- Object Number:
- 1926-716
- type:
- magnet
- credit:
- Sir Oliver Lodge.
