Low Characteristic Impedance Research Articles

Ein Kabelverstärker für Impulse grosser amplitude

Zusammenfassung A detailed circuit is given that feeds large fast pulses into the low characteristic impedance of a cable with a gain of unity. Its output impedance is 3ω, its risetime less than 0.1 μsec. When working into a 150ω cable, the linearity is better than 1% for positive pulses up to 120 V.

Some considerations of the magnetostrictive composite oscillator method for the measurement of elastic moduli

The development of the composite oscillator method, using nickel transducers, to enable measurement of the rigidity moduli as well as the Young's moduli of small cylindrical specimens is described. The magnitude of the cementing errors for the different modes of excitation is examined both theoretically and experimentally. An analysis is given which shows the advantages, for the technique described, of resonating at the fundamental mode for specimens of relatively low characteristic acoustic impedance. A further consideration of errors due to cross-sectional mismatch between transducer and specimen is made and finally some measurements on coal specimens are given.

A High Intensity Short Duration Spark Light Source

The spark described here provides a high intensity light source, whose effective duration approaches 10−7 second. The light intensity is nine hundred times greater than that obtained using RG8U cable cut for 10−7 second duration discharge. The cable described here is coaxial with silver conductors fired on the dielectric, a compound of barium titanate. The gain in light intensity is apparently due to both the higher capacity of the barium titanate cable and its very low characteristic impedance.

The Duct Capacitor

This paper describes a new type of feed-through capacitor having outstanding capabilities in the suppression of radio interference, particularly at the higher frequencies. It is shown that the filtering obtained is of the nature of attenuation along a transmission line of high loss and low characteristic impedance. Furthermore, the construction is such that complete shielding can be obtained between the input and output leads. A description is given of a typical duct capacitor; also, two of the principal applications are discussed.