Acoustic resonances in HID lamps: model and measurement

A MHz Electronic Ballast for Automotive-Type HID Lamps

The compatibility of the Current Sourcing Push Pull Resonant Inverter (CS-PPRI) with the driving requirements of HID lamps designated for automotive headlight applications was investigated theoretically, by simulation and experimentally. The study reveals that a based ballast (CS-PPRI) complies with the automotive requirement of very fast warm up. The experimental ballast was run under Zero Vol...

High-Frequency Dimmable Electronic Ballast for Automotive HID Lamps

This paper presents a high-frequency electronic ballast for HID lamps. A new fixed frequency dimming method with low EMI features is developed in this research. The proposed electronic ballast has the advantages of high power density, simple circuit and low EMI features. The circuit operating principle and design procedures are described in detail. A laboratory prototype was built and tested. T...

Complex Resonances in Acoustic Waveguides

We consider a two-dimensional innnitely long acoustic waveguide formed by two parallel lines containing an arbitrarily shaped obstacle. The existence of trapped modes that are the eigenfunctions of the Laplace operator in the corresponding domain subject to Neumann boundary conditions was proved by Evans, Levitin & Vassiliev (1994) for obstacles symmetric about the centreline of the waveguide. ...

Rotational acoustic resonances in cylindrical waveguides

An investigation is made into the existence of rotational acoustic resonances in a circular cylindrical waveguide, and their frequencies of oscillation are calculated numerically. The guide is assumed to contain a number of radial fins which have finite extent, and which are distributed at equal azimuthal angles around the guide. A variational principle is used to prove the existence of differe...

Seismic resonances of spherical acoustic cavities