A STATIC RECORDER 



287 



width. It is desirable to have a loud speaker connected to the (jutput 

 of the set and occasionally listen for c.w. interference. 



The constant output control apparatus is shown in Fig. 3. The 

 fluxmeter is seen in the upper right corner. Full deflection corresponds 

 to 2 X 10-* coulomb. The needle is normally free to move except 

 when the cam Z presses the needle down until its point touches the 

 scale OS. The shaft carrying the cam Z and the disc N is rotated 



MOVING COIL 

 OF FLUXMCTERX 



LOW FREQ. 

 TRANSFORMER 



/ 



FROM LOW FREQ.f 

 AMPLIFIER (FI6-E 



DRIVEN BY CLOCK MOTOR 

 ONE TURN IN 15 5ECOND5 



H-'A,C AND D RELAYS 



^GAIN CONTROL MOTOR 

 " (SERIES WOUND) 



PAPER DRUM MAKES 

 ONE TURN IN Z HOURS 



TO SECOND STAGE \ FROM FIRST STAGE 



OF INT FREQUENCY ^OF INT FREQUENCY 



AMPLIFIER AMPLIFIER 



(SEE FIG-2) 



Fig. 3 — Schematic circuit of constant output control apparatus 



one complete turn in 15 seconds by a clock motor. The different 

 elements are explained in the figure and the whole action may be under- 

 stood by studying this carefully. However, it is probably worth 

 while to go through a complete 15 second period and explain in detail 

 the purpose of each part. 



Time in Seconds — 0-10: 



Switch G is open, therefore relay A is open and no current can pass through the 

 windings of relays C and D. (These relays start the gain control motor, which is 

 therefore shut off.) 



Contact 1 of relay A is closed and closes the circuit consisting of the secondary 

 winding of the low frequency output transformer, the rectifier for the static currents 



