A power source is proposed comprising an output for a load. The power source is configured to provide a first voltage at the output. The power source is configured to detect a feedback at the output. The power source is further configured to provide a second voltage at the output based on the detected feedback. A high second voltage is only provided if an appropriate load is detected. This has the advantage that people are protected from electric shock e.g. when handling unconnected cables.

Methods and apparatuses for detecting an open load condition for a load. The load is coupled to a power source at a high side and to a ground at a low side through at least one switch, the load has a first end and a second end, a first voltage at the first end is kept constant. A switch is controlled by a PWM signal. After the switch is turned off by the PWM signal, the voltage associated with the second end of the load is measured. In one embodiment, a change of the second voltage during a predefined delay is compared with a predefined voltage threshold. In another embodiment, the time it takes for the change of the second voltage to reach a predefined voltage threshold is compared with a predefined time threshold.

A digital power distribution system includes a source sensor configured to provide feedback that includes a signal indicative of voltage across the source terminals; a source controller configured to receive the feedback from the source sensor and to generate a control signal that substantially increases or decreases impedance between the power source and the source terminals; a non-linear load configured such that the electrical current it draws from the load terminals drops by at least an order of magnitude below a non-zero voltage threshold; reduced capacitance on the load side for storing charge and discharging that charge during the sample period, wherein the reduced capacitance is reduced to a level for providing the at-least-an-order-of-magnitude-lower electrical current drawn by the non-linear load below the voltage threshold; and a source disconnect device responsive to the control signal from the source controller.

A digital power distribution system includes a source sensor configured to provide feedback that includes a signal indicative of voltage across the source terminals; a source controller configured to receive the feedback from the source sensor and to generate a control signal that substantially increases or decreases impedance between the power source and the source terminals; a non-linear load configured such that the electrical current it draws from the load terminals drops by at least an order of magnitude below a non-zero voltage threshold; reduced capacitance on the load side for storing charge and discharging that charge during the sample period, wherein the reduced capacitance is reduced to a level for providing the at-least-an-order-of-magnitude-lower electrical current drawn by the non-linear load below the voltage threshold; and a source disconnect device responsive to the control signal from the source controller.

A device for permanently secure disconnection of an electric circuit with high currents at high voltages with an inductive load is provided. The device has a first and a second switch/switch group, connected to each other in series and can be transferred from a closed state into a separated state for disconnecting the electric circuit, wherein none of the switches/switch groups is formed such that it is capable of permanently disconnecting the electric circuit by itself, and a control unit, which actuates the second switch/switch group and which is formed such that the second switch/switch group is transferred from the closed state into the separated state after the first switch/switch group. Further provided is an electric circuit which includes the device and a voltage source, a load resistance and an inductive load. A method using the device is also provided.

A device for permanently secure disconnection of an electric circuit with high currents at high voltages with an inductive load is provided. The device has a first and a second switch/switch group, connected to each other in series and can be transferred from a closed state into a separated state for disconnecting the electric circuit, wherein none of the switches/switch groups is formed such that it is capable of permanently disconnecting the electric circuit by itself, and a control unit, which actuates the second switch/switch group and which is formed such that the second switch/switch group is transferred from the closed state into the separated state after the first switch/switch group. Further provided is an electric circuit which includes the device and a voltage source, a load resistance and an inductive load. A method using the device is also provided.

In a bridge circuit, a series circuit in which a first resistor and a second resistor are connected in series and the second resistor and a fourth resistor are connected in series is formed. In the bridge circuit, the series circuit is connected to a load portion in parallel, one end of a fifth resistor is connected between the second resistor and the fourth resistor, and the other end of the fifth resistor is connected between the first resistor and the load portion. In the bridge circuit, a voltage supply unit is connected between the first resistor and the second resistor. A controller detects an abnormality of the load portion based on a detection voltage of the bridge circuit detected by applying a voltage from the voltage supply unit with a switch turned off. With this configuration, an abnormality detection device can detect abnormality while suppressing an increase in size.

A monitor circuit that monitors power delivered by an electrical utility or other source to a consumer. The device may be located at or near an entry point, such as near an electrical meter. The device senses a material change in voltage, and terminates power to the consumer until normal voltage is restored. The device automatically resets when normal voltage is restored, without need for a service call.

A monitor circuit that monitors power delivered by an electrical utility or other source to a consumer. The device may be located at or near an entry point, such as near an electrical meter. The device senses a material change in voltage, and terminates power to the consumer until normal voltage is restored. The device automatically resets when normal voltage is restored, without need for a service call.

Isolation circuit system and a signal isolation method thereof. The system includes: a power management unit, configured to output a first signal to a digital logic circuit when power down is detected in a first circuit area, and output a second signal to the digital logic circuit when no power down is detected in the first circuit area; the digital logic circuit, configured to perform logical processing on the first signal received from the power management unit before outputting an isolation signal to the isolation circuit, and perform logical processing on the second signal received from the power management unit before outputting a connection signal to the isolation circuit; and the isolation circuit, configured to block the interactive signal, or to output the interactive signal to a second circuit area after the interactive signal is processed through voltage stabilization.