Western Electric Resistance Lamps

No. 12 Type

The No. 12 type resistance lamps are intended for use as current limiting devices in telephone service. They have a single tungsten filament and are equipped with a medium Edison screw base. The bulb is of clear tipless glass, approximately 7/8 inch indiameter. The maximum overall length is 3 inches.

The No. 12 type resistance lamps entirely replace the No. 8 type of corresponding code letter.

The average operating characteristics of these lamps are as follows:

Voltage across lamp measured at following specified currents through the lamp:

Code No. .03 Amp .06 Amp .08 Amp .10 Amp .20 Amp .25 Amp .50 Amp
12A 0.45 V 2.3 V 14.0 V
12B 20.0 V 64.0 V 110.0 V
12C 12.5 V 34.0 V 79.0 V
12D 7.0 V 1.50 V 31.0 V
12E 6.0 V 12.0 V 26.0 V
12F 2.0 V 6.0 V 18.0 V
12G 8.0 V 35.0 V 110.0 V
12H 2.0 V 4.5 V 20.0 V
12J 0.7 V 4.0 V 24.0 V

Code No.	.03 Amp	.06 Amp	.08 Amp	.10 Amp	.20 Amp	.25 Amp	.50 Amp
12A	0.45 V			2.3 V	14.0 V
12B	20.0 V	64.0 V	110.0 V
12C	12.5 V	34.0 V		79.0 V
12D	7.0 V	1.50 V		31.0 V
12E	6.0 V	12.0 V		26.0 V
12F				2.0 V		6.0 V	18.0 V
12G				8.0 V		35.0 V	110.0 V
12H		2.0 V		4.5 V		20.0 V
12J				0.7 V		4.0 V	24.0 V