1328 THE BELL SYSTEM TECHNICAL JOURNAL, NOVEMBER 1953 



Fig. 13 — Build-up of oscillation in resonant circuit. Normal operating conditions. 



the condition for oscillogram (b) with some transistors if the small emitter 

 bias current had not been provided. 



TRANSIENT EFFECTS 



The trunk conductors are balanced with respect to ground. Voltages 

 set up in these conductors due to electrostatic or magnetic coupling to 

 the source of the interference will cause longitudinal currents to flow. 

 An electrostatic shield in the transformer, shown in Fig. 1, effectively 

 prevents such longitudinal currents from reaching the oscillator circuit. 



c 



^f 



■VA ' 



Fig. 14 — Equivalent resonant circuit. 



