. Some experiments with coupled high-frequency circuits . itude of the oscillations. It appears desir-able that further quantitative data on this subject should be givenand it is with this object that the present work has been taken up. ^ C. Fischer, Ann. d. Phys., vol. 22, p. 265, 1907. 301 302 Bulletin of the Bureau of Standards Woi. 7. No. 2 2. THE SOURCE OF THE OSCHLATIONS For convenience in experimentation it was desired to set upthe apparatus in a moderately small space, and this precludedthe use of powerful spark apparatus on accotmt of the directaction of the spark circuit on the detec
. Some experiments with coupled high-frequency circuits . itude of the oscillations. It appears desir-able that further quantitative data on this subject should be givenand it is with this object that the present work has been taken up. ^ C. Fischer, Ann. d. Phys., vol. 22, p. 265, 1907. 301 302 Bulletin of the Bureau of Standards Woi. 7. No. 2 2. THE SOURCE OF THE OSCHLATIONS For convenience in experimentation it was desired to set upthe apparatus in a moderately small space, and this precludedthe use of powerful spark apparatus on accotmt of the directaction of the spark circuit on the detecting devices. Experi-ment showed that when feeble sparks carrying only a few milli-amperes were employed undesirably large damping was intro-duced into the sending circuit. The buzzer method of excitingfeebly damped oscillations by the whip-crack discharge,^ it wasfound, did not give sufficient energy for the present a satisfactory form of buzzer circuit^ was determined on,which is shown in Fig. i. In this B is a United States Signal SZ=. ^^/wv\^ Fig. 1 Corps buzzer of the 1905 type excited by two storage cells witha regulating resistance and key in series. The oscillatory circuitwhich is connected around the break of the buzzer consisted of avariable air condenser Cj, having a maximum capacity of and an inductance L^ of 20 tiuns of No. 20 wirewound in a coil of approximately 10 cm diameter.* The valueof this inductance was millihenrys. This circuit, when the buzzer was properly adjusted, gave outvery feebly damped oscillations, the logarithmic decrement, whenno extra resistance was introduced, being between i and 2 percent. 2 M. Wien, Ann. d. Phys., 25, p. 625, 1908, and L. W. Austin, this Bulletin, C, ; 1908. ^ L. W. Austin, this Bulletin, 6, p. 528; 1910. * It is to be understood that all the inductances employed in the work were woundin single layers. Austin] Coupled High-Frequency Circuits 303 With a proper adjustment of the buzz
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