Abstract: A magnetic coupler for magnetically or inductively coupling a pair of conductors. The coupler includes a first magnetic core member having prongs and at least one slot between the prongs for receiving the conductors, and a second magnetic core member. The coupler further includes a base for retaining the first core member and a shuttle for retaining the second core member. The shuttle is slidably mounted within the base such that the shuttle slides across and in contact with the prongs from an open position in which the slot is exposed to a closed position in which the slot is covered by the second core member, and the conductors are thereby contained within the slot. The sliding action of the cores cleans debris off the mating surfaces of the core elements to provide good mating contact between the core members for efficient coupling.

Abstract: A product information display system has electronic display tags for displaying pricing and product information for products in stores or warehouses. The electronic display tags are electromagnetically coupled to a conductor. A control circuit is used to generate an information signal which contains a tag address and related data. A modulator circuit modulates an ac power signal with the information signal and applies it to the conductor for transmission to the display tags. Each of the display tags is equipped with a coil that is electromagnetically coupled to the conductor for picking up the signals carried by the conductor. A demodulator is used to demodulate the signal picked up by the coil to obtain the original information signal. Each of the display tags is provided with a manually operated switch for initializing the tags with initial addresses transmitted by the conductor.

Abstract: A power supply system includes an a-c. power source and an off-line power supply for storing energy from the a-c. power source during first selected time intervals and converting at least a portion of the stored energy to a d-c. output during second selected time intervals. A diode or other switch disconnects the off-line power supply from the a-c. power source during the second selected time intervals to reduce conducted EMI. The first and second selected time intervals are preferably synchronized to the frequency of the a-c. power source.

Abstract: A product information display system has electronic display tags for displaying pricing and product information for products in stores or warehouses. The electronic display tags are electromagnetically coupled to a conductor. A control circuit is used to generate an information signal which contains a tag address and related data. A modulator circuit modulates an a-c. power signal with the information signal and applies it to the conductor for transmission to the display tags. Each of the display tags is equipped with a coil that is electromagnetically coupled to the conductor for picking up the signals carried by the conductor. A demodulator is used to demodulate the signal picked up by the coil to obtain the original information signal. Each of the display tags is provided with a manually operated switch for initializing the tags with initial addresses transmitted by the conductor.

Abstract: A product information display system has electronic display tags for displaying pricing and product information for products in stores or warehouses. The electronic display tags are electromagnetically coupled to a conductor. A control circuit is used to generate an information signal which contains a tag address and related data. A modulator circuit modulates an a-c. power signal with the information signal and applies it to the conductor for transmission to the display tags. Each of the display tags is equipped with a coil that is electromagnetically coupled to the conductor for picking up the signals carried by the conductor. A demodulator is used to demodulate the signal picked up by the coil to obtain the original information signal. Each of the display tags is provided with a manually operated switch for initializing the tags with initial addresses transmitted by the conductor.

Abstract: A miniaturized switching power supply has an output circuit for supplying gate drive to a power FET. The output circuit incorporates a pair of series connected transistors with a zener diode connected to the base of one of the transistors to limit the gate drive to the FET.

Abstract: A high frequency miniaturized switching power supply has a unidirectional spike filter which removes spikes appearing on a feedback signal before such feedback signal is provided to the comparator of the switching power supply. The spike filter removes voltage spikes of one polarity without lengthening the reset time of the comparator in response to a wavefront of the opposite polarity.