. The Bell System technical journal . g the influence of interelectrode capacitances on the frequency shown in Fig. It is pointed out that the effect of the crystal resistanceRi is to decrease the frequency for the G-C connection and increase thefrequency for the G-P connection. The discrepancy between the measured PIEZOELECTRIC CRYSTALS IX OSCILLATOR CIRCUITS 173 and experimental values shown on the curves is attributed to the differencebetween chosen and actual value of Ri. The effect of the input loss of thetube is not shown because the grid current was disregarded; however, thisloss
. The Bell System technical journal . g the influence of interelectrode capacitances on the frequency shown in Fig. It is pointed out that the effect of the crystal resistanceRi is to decrease the frequency for the G-C connection and increase thefrequency for the G-P connection. The discrepancy between the measured PIEZOELECTRIC CRYSTALS IX OSCILLATOR CIRCUITS 173 and experimental values shown on the curves is attributed to the differencebetween chosen and actual value of Ri. The effect of the input loss of thetube is not shown because the grid current was disregarded; however, thisloss may be reduced to an equivalent Ri . The resistance of the plate cir-cuit i?2 affects the frequency in a similar manner. The effects of theseresistances on frequency are less for low values of plate circuit required value of Rp gives a measure of amplitude of oscillationbecause it is necessary for oscillations to build up until the internal plateresistance is equal to the calculated value. It is found that Rp increases. Fig. —Experimental curves, showing the relation between the frequency and theresistance of the oscillatory circuit gradually to a maximum as tlie common frequency for the two types ofcircuits is approached then abruptly drops. Vigoureux analyzes the crystal oscillator in a manner similar toTerry and correlates his interpretations of the equations with considerableexperimental data, some of which are shown in Figs. , , He points out that there is an optimum value of grid capacitancewith the cr>stal connected between grid and plate and a certain amountof grid-plate capacitance is required when the crystal is connected betweengrid and cathode. Wheeler does not assume a linear static tube characteristic butrepresents it by a three-term nonlinear expression. The results are morecomplex and it is necessary in the end to disregard certain resistance terms. 174 BELL SYSTEM TECHNICAL JOURNAL 40 fo G-C
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