//iV ELECTRICAL FREQUENCY ANALYZER 



309 



that the analyzer is equipped to trace two curves simultaneously 

 on a single record. This is accomplishctl by means of air relay B 

 which is so arranged as to connect two sources of input alternately 

 to the analyzer. These input connections are alternatcti rapidly 

 and are effected by appropriate punching of the roll. 



The above covers the essential features of the aiialvzcr but there 



Fig. 6— View of .■\nalyzer with Relay .Side Uncovered 



a — Input and tuned circuits 



b — .Amplifier-rectifier 



c — Camera motor 



d — RecordinR meter 



e — Control Im.x 



( — Starting button 



-Main header 



h — Condenser relays 

 I — Holding relay 

 j — Frequency lamp relay 

 k — Main control relay 

 / —Plate battery 

 -.Air motor 



remain a few details having to do with assembly, control, etc., that 

 may be of interest. 



Fig. 5 shows the analyzer as completed and ready to operate. The 

 apparatus is assembled on a two-deck, structural-steel table equip- 

 ped with castors for convenience in handling. Much of the equip- 

 ment is inclosed for protection against moisture and dust. The 

 recording meter, camera motor, amplifier-rectifier, control relays, 

 and input and tuned circuits are placed on the top. Below are 



