Abstract: An audio entertainment system having a primary circuit board with a processor in communication with an antenna input, an audio output and a connector. The processor is configured to detect the presence of the digital audio circuit board and to output an audio signal to the audio output based on the wireless signal. The wireless signal may be an AM, FM or digital satellite signal.

Abstract: An audio entertainment system having a primary circuit board with a processor in communication with an antenna input, an audio output and a connector. The processor is configured to detect the presence of the digital audio circuit board and to output an audio signal to the audio output based on the wireless signal. The wireless signal may be an AM, FM or digital satellite signal.

Abstract: A method to absorb magnetic fields begins by placing an electronic unit into a fixture. The electronic unit contains at least one electrical component, such as a microchip, that requires a reduction of a magnetic field. The microchip can be surrounded by a containment apparatus, such as a mold, into which encapsulant is poured. Exclusion devices, such as masks, protect components that should not be coated. Once the electronic unit is prepared, it is exposed to magnetic field interference. At this point, encapsulant is poured into all molds on the electronic unit. Ferrite particles comprise a portion of the encapsulant and initially are randomly distributed throughout. When the ferrite particles are exposed to a magnetic field, they migrate along the generated field lines and absorb the magnetic field. After the new distribution of ferrite particles occurs, the encapsulant can be cured.

Abstract: An active clamp circuit for an inductive load switching circuit includes a zener current control resistor to set the breakdown current in a zener diode of the clamp circuit. The zener breakdown current is set at a sufficiently high level to ensure that the zener diode is operated at a point beyond its "knee" region and therefore does not generate interfering levels of microplasmic noise (MPN). The zener current control resistor is provided in addition to a circuit speed control resistor such that there is substantially independent control of the switching circuit operating speed and the breakdown current of the zener diode of the active clamp circuit.