Accession No

3353

Brief Description

resistance box, low inductance resistance, by Cambridge Instrument Company Ltd., English, 1929

Origin

England; London

Maker

Cambridge Instrument Company Ltd.

Class

electrical

Earliest Date

1929

Latest Date

1929

Inscription Date

Material

wood; plastic (ebonite); metal (brass, other, foil); ceramic

Dimensions

length 306mm; breadth 222mm; height 160mm

Special Collection

Provenance

Transferred from Department of Engineering, University of Cambridge, Cambridge, England, 1986.

Inscription

‘OHMS
AT
20 C
EURELA
LOW INDUCTANCE
RESISTANCE
CAMBRIDGE
INSTRUMENT CO. LTDL, ENGLAND.
No. L-34950 (with logo)’ (on top)
‘ENG. LAB.
CAMB. UNIV.’ (on top, added)

Description Notes

Rectangular wooden box with ebonite top; three brass terminals (one to ‘SCREEN’); five eleven-position rotary switches with ebonite knobs and metal pointers (0 to 1, 10, 100, 1000, and 10000 ohms); each switch has a different maximum current rating stamped on top; the different resistors consist variously of metal strips, coils wound on ceramic bobbins, and coils wound on composition plates, fastened to underside of top plate; box lined with metal foil as shield. Wooden lid with hand-lettered calibration table inside, providing resistances and residual inductances, measured at 1000 hertz for each dial setting.

Condition: good; complete.

References

Events