Abstract: An illumination device includes a light tube holder including two connectors for receiving either a light-emitting diode (LED) tube or a fluorescent tube. The connector includes a rotary member rotatably received in a through hole defined in a retainer, and three conductive elastic pieces positioned in the retainer around the through hole. One elastic piece is electrically connected to an LED tube drive circuit board, and the other two elastic piece are electrically connected to a fluorescent tube drive circuit board. The rotary member can be rotated to first and second positions, wherein at the first position, the LED tube can be activated, and at the second position the fluorescent tube can be activated. The LED tubes has two conductive pins at each end thereof. The LED tube can be mounted to the connectors regardless an orientation of the LED tube.

Abstract: An illumination device includes a light tube holder including two connectors for receiving either a light-emitting diode (LED) tube or a fluorescent tube. The connector includes a rotary member rotatably received in a through hole defined in a retainer, and three conductive elastic pieces positioned in the retainer around the through hole. One elastic piece is electrically connected to an LED tube drive circuit board, and the other two elastic piece are electrically connected to a fluorescent tube drive circuit board. The rotary member can be rotated to first and second positions, wherein at the first position, the LED tube can be activated, and at the second position the fluorescent tube can be activated. The LED tubes has two conductive pins at each end thereof. The LED tube can be mounted to the connectors regardless an orientation of the LED tube.

Abstract: A lamp tube switch circuit supplies power to a selected LED/fluorescent lamp tube connected between first and second connectors and comprises a ballast and a starter. A power supply has positive and negative terminals. A switch module comprises first, second and third switches each having a first end connecting with the positive terminal, fourth and fifth switches each having a first end connecting with the negative terminal and a sixth switch having a first end connecting with the first connector. A button module has six buttons one of which is correspondent to the selected lamp tube. A control unit is connected to the button module, and functions to turn on and turn off the switches with a predetermined mode according the selected lamp tube.

Abstract: An RF microwave power transistor has an input/output feed structure which functions as a low impedance microstrip line by providing a ground plane in close proximity to the feed structure on one surface of a semiconductor body. A second ground plane can be provided on an opposing surface of the semiconductor body with vias interconnecting the first and second ground planes. In addition to reducing feed impedance, a larger total transistor size can be provided before “odd mode oscillation” occurs.

Abstract: Efficiency of an RF/microwave power amplifier is increased at a back-off power level by increasing the load resistance of the amplifier at the reduced output power level as compared to load impedance at a higher power level including full operating power. The different load impedances can be realized with two amplification units in parallel each having different load impedances. Alternatively, a single amplification path can be provided with an output impedance matching network which is selectively bypassed for increased impedance load during back-off power operation. In another embodiment, the output impedance matching network can include a shunt inductance which is selectively switched into the network to increase impedance for back-off power operation.

Abstract: In an RF amplifier circuit having a plurality of transistor stages with each transistor having an input terminal for receiving an RF signal, a bias circuit is provided for applying a DC bias to the input terminal of a transistor. An isolation circuit connects a DC power supply to a bias circuit whereby DC voltage from the power terminal is applied to the bias circuit and RF signal from the transistor input terminal is attenuated. The isolation circuit includes a reactive serial path which allows the flow of DC current and presents an impedance to RF current flow and a reactive shunt path to ground which can comprise a capacitor or a serial inductor/capacitor circuit. The reactive serial path can comprise an inductor or an inductor/capacitor parallel circuit.