To 6SJ7 3 amp 

 Heaters Only 



To Heaters on both 

 Ctiassis 10 amp 



Figure 5 - Schematic Wiring Diagram of the Power Supply- Amplifier Unit 

 of the Type 145-A Dynamic Wave-Height Recorder 



OPERATION 



For operation the instrument may be powered from any source of 115-volt, 60-cycle, 

 single-phase voltage capable of furnishing at least 300 watts of power. The gaging element 

 should be mounted on a rigid support in such a manner that approximately half the length of 

 the insulated wire is submerged. One such support designed for use at the Model Basin is 

 equipped with a fine screw adjustment by which the gaging element can be raised or lowered 

 in the water. This permits a simple and direct means of calibrating the entire system. After 

 the instrument has been turned on for about five minutes or more and the gaging wire has been 

 placed at the desired point, the operator may proceed to balance the bridge by means of the 

 controls provided for this purpose. Bridge balance is obtained in the usual manner prescribed 

 for balancing a-c bridges, utilizing the null indicator meter deflections as a guide. Maximum 



