Abstract: A device includes a connection receiving power from a power source under normal conditions and circuitry configured to determine, based on an input from the connection, when the power from the power source is absent; output, when the power source is absent, a test signal at the connection; and generate a detection signal based on current flow generated following the output of the test signal, wherein the detection signal indicates a position of a switch connecting the circuitry to the connection and the generated detection signal indicates the switch is closed when the current flow is above a threshold. The circuitry is configured such that when the power from the power source is absent, the switch is dosed, and plural devices are connected on the supply side of the switch, the plurality of devices on the supply side appear as a substantially open circuit to the test signal.

Abstract: A device includes a connection receiving power from a power source under normal conditions and circuitry configured to determine, based on an input from the connection, when the power from the power source is absent; output, when the power source is absent, a test signal at the connection; and generate a detection signal based on current flow generated following the output of the test signal, wherein the detection signal indicates a position of a switch connecting the circuitry to the connection and the generated detection signal indicates the switch is closed when the current flow is above a threshold. The circuitry is configured such that when the power from the power source is absent, the switch is closed, and plural devices are connected on the supply side of the switch, the plurality of devices on the supply side appear as a substantially open circuit to the test signal.

Abstract: A device includes a connection receiving power from a power source under normal conditions and circuitry configured to determine, based on an input from the connection, when the power from the power source is absent; output, when the power source is absent, a test signal at the connection; and generate a detection signal based on current flow generated following the output of the test signal, wherein the detection signal indicates a position of a switch connecting the circuitry to the connection and the generated detection signal indicates the switch is closed when the current flow is above a threshold. The circuitry is configured such that when the power from the power source is absent, the switch is closed, and plural devices are connected on the supply side of the switch, the plurality of devices on the supply side appear as a substantially open circuit to the test signal.

Abstract: A light fixture with a motion sensor includes a holder arranged for mounting on either a vertical or a horizontal surface, a head rotatablely connected with the holder, and a motion sensor installed on the holder, the head including a housing, a control circuit board and multiple light bulbs mounted in the housing, the light bulbs and the motion sensor being electrically connected with the control circuit board, the motion sensor being arranged to receive infrared radiation emitted by a human being thereby turning on the light bulbs controlled by the control circuit board. The head is rotatable, thus the illumination angle of the light fixture is wide, and is convenient to operate.