General Information

Serial #

N/A

Part Number

1

Total Parts

1

AKA

N/A

Patents

N/A

General Description

CAST IRON FRAME, STEEL MAGNET ASSEMBLY, BRASS CLAMPING BARS, COTTON COVERED MAGNET WIRE SOLINOIDS

Dimensions

Note: These reflect the general size for storage and are not necessarily representative of the object's true dimensions.

Length

15.0 cm

Width

11.0 cm

Height

6.5 cm

Thickness

N/A

Weight

N/A

Diameter

N/A

Volume

N/A

Lexicon

Group

Communications

Category

Telephony

Sub-Category

N/A

Manufacturer

AKA

Unknown

Country

United States of America

State/Province

Unknown

City

Unknown

Context

Country

North America

State/Province

Unknown

Period

1877 TO 1887

Canada

PATENTED BY ALEXANDER GRAHAM BELL IN 1877, BASED ON RESEARCH CARRIED OUT AT BRANTFORD, ON. & BOSTON, MA.

Function

USED TO CONVERT VOICE SOUNDS INTO VARYING ELECTRIC CURRENT BY THE ACTION OF A STEEL DIAPHRAGM VARYING THE MAGNETIC FIELD SUPPLIED BY THE LARGE MAGNET ASSEMBLY. IT COULD ALSO BE USED AS A RECEIVER WITH VARYING CURRENT APPLIED TO THE COILS WHICH WOULD INCREASE & DECREASE THE MAGNETIC FIELD & THUS CAUSE THE STEEL DIAPHRAGM TO MOVE, PRODUCING SOUND.

Technical

FIRST TYPE OF TELEPHONE TRANSMITTER IN COMMERCIAL SERVICE, 1877-1878. IT CONSISTED OF A METAL DIAPHRAGM FIXED IN THE FIELD OF A PERMANENT MAGNET WITH A VOICE COIL WOUND AROUND THE MAGNET'S POLES. VIBRATION OF THE DIAPHRAGM BY SOUND WAVES CAUSED A VARIATION OF THE MAGNETIC FIELD & INTRODUCED A VARYING CURRENT IN THE VOICE COIL, WHICH WAS TRANSMITTED OVER A TELEPHONE WIRE. IT WAS SOON SUPERSEDED BY THE CARBON VARIABLE RESISTANCE TRANSMITTER, WHICH PROVIDED MORE POWERFUL SIGNALS.

Area Notes

Unknown

Details

Markings

'36' WRITTEN IN WHITE PAINT ON FRONT OF CASTING

Missing

DIAGRHAM, MISC. HARDWARE AND WALL MOUNTING CASE

Finish

FRAME, BLACK ENAMEL

Decoration

N/A