MVWEPS REPORT 76^0 



and E, is in phase with E, 

 5 1 



and at the balance frequency E. is in phase with E^ 



where 



^1 = \ - 2^^^ 

 I- = I- . J2.fC^ 



at the balance frequency f = _, ^^ - ^ 



^ *' o 2jtR,C-. 



and 



Z^ = (1 - j)R^ 

 (1 - o)R. 



^2 = 2-^ 



hence E,, = ■=- E^ at f = f 

 431 o 



If a null is desired, R2 must equal 2R2 so that E2 = Eij. - E2 = 0. 

 However, if the bridge is to be used as the feedback network for an 

 oscillator, the magnitude of p must not be zero althoixgh the phase shift 

 must be kept at zero. The preceding may be done by taking the ratio of 

 R2/(R2 + R5) smaller than I/3, i.e., let 



^3 ^3 1 1 

 \ ^2 + R3 3 o 



where a is larger than 3. 



At f = f Q and p = l/a, the condition Ap = 1 may be realized by 

 making A = a. 



As shown in the preceding, the impedance of the bridge as seen from 

 output and input varies as a function of R. Therefore, in order to 

 operate the oscillator over a wide frequency range, it is necessary to 



10 



