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