Provided is a power detection circuit for tracking a maximum power point of a solar cell. The power detection circuit includes: an average voltage extracting unit which extracts an average voltage V.sub.PV,LPF from an external voltage V.sub.PV input from an external energy source; a ripple voltage extracting unit which extracts a ripple voltage including current information of the external voltage V.sub.PV from the external voltage V.sub.PV; a voltage-time converter which generates a ramp voltage V.sub.RAMP changing at a predetermined rate and converts the average voltage V.sub.PV,LPF and the ripple voltage into corresponding time information t.sub.1 and t.sub.2 based on the ramp voltage V.sub.RAMP; a time-digital converter which converts the time information t.sub.2 for the ripple voltage into a digital code t.sub.2 [n:0]; and a time multiplier which multiplies the digital code t.sub.2 [n:0] and the time information t.sub.1 for the average voltage V.sub.PV,LPF to output a specific voltage value.

A measurement device providing a graphical user interface (GUI) to a user on a remote terminal comprising at least one first processor; and at least one first memory including one or more first sequences of instructions to perform the steps of transmitting a GUI displaying a at least one of a first, a second, a third, and a fourth image in response to at least one of a voltage characteristic, a current characteristic, and a load characteristic obtained from the user through the GUI on the remote terminal. Then, the measurement device stores in a memory the at least one of the voltage characteristic, the current characteristic, and the load characteristic.

A measurement device providing a graphical user interface (GUI) to a user on a remote terminal comprising at least one first processor; and at least one first memory including one or more first sequences of instructions to perform the steps of transmitting a GUI displaying a at least one of a first, a second, a third, and a fourth image in response to at least one of a voltage characteristic, a current characteristic, and a load characteristic obtained from the user through the GUI on the remote terminal. Then, the measurement device stores in a memory the at least one of the voltage characteristic, the current characteristic, and the load characteristic.

A measurement device, such as a power meter or power submeter, may comprise a frame disposed in a housing dividing an interior volume of the housing into a first volume and a second volume. An external power source is connected to the device in the first volume and the frame may serve as an insulative barrier between the first volume and an exterior it and the housing. The device may alternatively, or additional include, an user interface assembly that is configured to mounted in a same orientation regardless of an orientation of the device or housing of a device relative to the external power source.

An apparatus for determining the occurrence of a leakage current between a series connected electrochemical battery cells, comprising: a first cell connection terminal for connection to a first cell's first terminal via first filter circuitry; a second cell connection terminal for connection, via second filter circuitry, to a connection between the first cell's second terminal and a second cell's first terminal, the first and second cell adjacent in the series arrangement; a first cell balancing terminal for connection to the first cell's first terminal bypassing the first filter circuitry; a second cell balancing terminal for connection to the connection between the first cell's second terminal and the second cell's first cell terminal; balancing circuitry for providing a connection between the cell balancing terminals; the apparatus configured to provide for identification of a leakage current based at least on a voltage between the cell connection terminals and the cell balancing terminals.

An apparatus for determining the occurrence of a leakage current between a series connected electrochemical battery cells, comprising: a first cell connection terminal for connection to a first cell's first terminal via first filter circuitry; a second cell connection terminal for connection, via second filter circuitry, to a connection between the first cell's second terminal and a second cell's first terminal, the first and second cell adjacent in the series arrangement; a first cell balancing terminal for connection to the first cell's first terminal bypassing the first filter circuitry; a second cell balancing terminal for connection to the connection between the first cell's second terminal and the second cell's first cell terminal; balancing circuitry for providing a connection between the cell balancing terminals; the apparatus configured to provide for identification of a leakage current based at least on a voltage between the cell connection terminals and the cell balancing terminals.

An abnormality determiner turns OFF a third switch and controls a converter controller to stop operating in a case where a voltage value detected by a voltage detector during a normal mode exceeds a first threshold value. The abnormality determiner determines that a first switch has an abnormality in a case where the voltage value exceeds a second threshold value in a state where the converter controller is stopped. The abnormality determiner controls the converter controller to operate in a case where the voltage value is equal to or smaller than the second threshold value in a state where the converter controller is stopped. The abnormality determiner determines that the converter controller has an abnormality in a case where the voltage value exceeds a third threshold value in a state where the converter controller is operated.

An abnormality determiner turns OFF a third switch and controls a converter controller to stop operating in a case where a voltage value detected by a voltage detector during a normal mode exceeds a first threshold value. The abnormality determiner determines that a first switch has an abnormality in a case where the voltage value exceeds a second threshold value in a state where the converter controller is stopped. The abnormality determiner controls the converter controller to operate in a case where the voltage value is equal to or smaller than the second threshold value in a state where the converter controller is stopped. The abnormality determiner determines that the converter controller has an abnormality in a case where the voltage value exceeds a third threshold value in a state where the converter controller is operated.

A method for checking quality when resistance-welding workpiece includes pressing welding electrodes with an electrode force against a weld spot of the workpieces using an electrode drive and energizing the welding electrodes with a welding current for a duration of a welding time in order to liquefy a surface of the workpieces. The method further includes determining, at a first time before a beginning of the liquefaction, a first value of a welding electrode parameter identifying a position of one or both electrodes, and determining, at a second time after the beginning of the liquefaction, a second value of the welding electrode parameter identifying a position of one or both electrodes. The method further includes comparing the first value and the second value and, evaluating a quality of the welding process based on the comparison.

A method for checking quality when resistance-welding workpiece includes pressing welding electrodes with an electrode force against a weld spot of the workpieces using an electrode drive and energizing the welding electrodes with a welding current for a duration of a welding time in order to liquefy a surface of the workpieces. The method further includes determining, at a first time before a beginning of the liquefaction, a first value of a welding electrode parameter identifying a position of one or both electrodes, and determining, at a second time after the beginning of the liquefaction, a second value of the welding electrode parameter identifying a position of one or both electrodes. The method further includes comparing the first value and the second value and, evaluating a quality of the welding process based on the comparison.