. The Bell System technical journal . C2—► C2—^ A B Fig. —The variation of grid to cathode capacitance (A) and oscillator frequency(B) with change in plate circuit capacitance. Crystal connected grid to cathode until the equality is satisfied. The difference between the positive andnegative terms is therefore a measure of the amplitude of () may be written b+^] ^ -1 $n + — I = ^ where yl is a measure of the amplitude, Rr () \p — mCsWo \ r ~ »-0 L2 I \CO0 L2 / 1 + R\(-^ - W0C2) () and^, = R 2/Co + C4Y Co C4 Co + C4 + C„ + C3 + liCz 1 + Kp\ — CO0C2 I \co
. The Bell System technical journal . C2—► C2—^ A B Fig. —The variation of grid to cathode capacitance (A) and oscillator frequency(B) with change in plate circuit capacitance. Crystal connected grid to cathode until the equality is satisfied. The difference between the positive andnegative terms is therefore a measure of the amplitude of () may be written b+^] ^ -1 $n + — I = ^ where yl is a measure of the amplitude, Rr () \p — mCsWo \ r ~ »-0 L2 I \CO0 L2 / 1 + R\(-^ - W0C2) () and^, = R 2/Co + C4Y Co C4 Co + C4 + C„ + C3 + liCz 1 + Kp\ — CO0C2 I \coo Li / _ () PIEZOELECTRIC CRYSTALS IN OSCILLATOR CIRCUITS 181 where again Rl is assumed small compared to 1 cooLi — OJoCl COo(Co I T + C.)J and Wo is considered a constant. Equation () shows that in order to obtain a large amplitude ypshould be large and $o should be small. With this in mind equations () pMC-)oC3. Fig. —Functions from which the activity variations (A) are determined as theplate circuit capacitance is varied. Crystal connected grid to cathode and () may be analyzed to determine the relation between the circuitcomponents and amplitude. It is found that for maximum amplitude Cg and Ri should be small,C4 should be large,Cz has an optimum value, andRg should be large. As to the plate circuit, the amplitude is maximum when R. 1 oooLi C00C2. A plot of ^ and $0 + — is shown in Fig. The difference between these two curves is a measure of the amplitude and is shown by curve ,1. Oscillations can exist only where \}/ lies over $0 + ^ • The sharp- Rgness of \p varies considerably with the value of Rp and the resistance of theL2 — Co circuit. The latter is disregarded for simpHcity. Here again the 182 BELL SYSTEM TECHNICAL JOURNAL results can only be considered a first approximation, but agree with actualconditions sufficiently to be of considerable interest. C
Size: 2024px × 1234px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
