摘要:

In a simple direct current feed‐back amplifying circuit it is necessary to readjust the input grid bias each time the amplification is changed. A modified circuit is described whereby this difficulty of operation is eliminated.

ISSN:0034-6748    

DOI:10.1063/1.1748683

出版商:AIP    

年代:1930

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1748684

出版商:AIP    

年代:1930

数据来源: AIP

摘要:

With the recent advances in photoelectric cell technique a number of experimenters have endeavored to devise a method of using vacuum tube amplification for the measurement of weak currents and small emf's. Among these may be mentioned Wynn‐Williams1and Eglin2who have developed a balanced bridge amplifier of high sensitivity; also Razek and Mulder3 4who have devised two single‐tube circuits. The single tube circuit does not possess the sensitivity of the balanced bridge circuit but has certain advantages in the way of simplicity of operation and control. Under proper conditions it may be used in a multi‐stage amplifier, using the principle of resistance‐coupling.

ISSN:0034-6748    

DOI:10.1063/1.1748685

出版商:AIP    

年代:1930

数据来源: AIP

摘要:

One stage of amplification included in the stabilizing circuit of the Bedell‐Reich oscilloscope, which comprises a cathode‐ray tube with linear time‐axis for observation of periodically varying quantities, extends the frequency range of the instrument and permits stabilization without disturbance to the circuit under test. Although not primarily intended for use beyond the audio range, the instrument has in this way been stabilized above 100,000 cycles. Curves are given showing the use of the instrument for the study of non‐electrical quantities (as sound and light) as well as of electrical quantities (as in the study of modulation and rectification).

ISSN:0034-6748    

DOI:10.1063/1.1748686

出版商:AIP    

年代:1930

数据来源: AIP

摘要:

An eliminator for full‐wave rectification (600 v) or half‐wave rectification (1200 v) with adjustable taps for all intermediate voltages, while introducing no new principle, gives a desirable flexibility for laboratory purposes. Ripple voltage, determined by the Bedell‐Reich Stabilized Oscilloscope, is found to be unusually small.

ISSN:0034-6748    

DOI:10.1063/1.1748687

出版商:AIP    

年代:1930

数据来源: AIP

摘要:

A method of measuring capacitance and inductance is described, in which the productLCis found in terms of frequency by adjusting a circuit which contains the capacitance and an inductance to resonance, the ratioL/Cis found in terms of resistance by a high frequency bridge, and the value ofCis finally calculated by solving the two equations forLCandL/Csimultaneously. A method of eliminating the effect of condenser leads is described. The bridge equations are derived and the effects of residuals in the arms are discussed. Details are given concerning the construction of the bridge, the oscillators, and the heterodyne detector, and concerning essentials of the operating technique. Numerical results are given for a sample condenser calibration.

ISSN:0034-6748    

DOI:10.1063/1.1748688

出版商:AIP    

年代:1930

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1748689

出版商:AIP    

年代:1930

数据来源: AIP