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THE BELL SYSTEM TECHNICAL JOURNAL, APRIL 1951 



number are used as single elements to perform such functions as vario- 

 losser bias control, rectifier, channel demodulator, keyer for signaling fre- 

 quency, voltage doubler in the signaUng circuit and current divider in the 

 expandor circuit. The remainder are assembled into three groups of care- 



r-GFRMANnjM WAf=ER 



I i^'. 5 Oermanium varistors. Lower right: Germanium varistor unit with an exploded 

 view directly above; Top: Magnified cross section of the same unit. The functional ele- 

 ments are a wafer of germanium which is soldered to the fluted pin at the left and the 

 "S" shaped tungsten wire in the pin at the right. The rectifying junction produced under 

 the tungsten point contact with the specially prepared germanium surface is the seat of 

 the non-linear resistance characteristic. Lower left: Vario-losser assembly. 



fully selected units, for use as the channel modulator, the compressor vario- 

 losser and the expandor vario-losser respectively. The germanium varistor 

 unit is shown at the lower right of Fig. 5. 



The compandor vario-losser varistors are of special interest because of the 

 important function they perform and the way in which the desired close 



