nFSlGX CH.IRACTF.RISTICS OP r.I.ECI ROM AGS' ETS 207 



construction ilitTcrs nialori.ilU in rii^jgctlness from tlie construction 

 where relatively small currents are to be controlled. In the opera- 

 tion of the relays larger amoimts of power, of course, are retjuired 

 for those having the more rugged construction. It is also evident 

 that more power is recjuired for fast operation than for comparatively 

 slow operation. Fast operation of relays is also dependent upon 



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Y\%. 1 — Spring Combinations Flat T\(x- Relay 



circuit arrangements which are effective in lowering the electrical 

 "time constant" of the circuits in which the relays operate. 



Electromagnets in telephone systems are designed and used for a 

 great variety of conditions. The more common uses are for relay 

 operation on direct current battery of 20 to 28 volts or 40 to 45 volts. 

 Such relays perform a great number of switching functions, a few of 

 which are shown in I'igs. 1 and 12. Other designs are used for oper- 



