A display device including a first substrate including a display area and a non-display area, a circuit film connected to the first substrate, a printed circuit board (PCB) connected to the circuit film, and a first inspection pad, a second inspection pad, and a third inspection pad located in the non-display area and a bridge configured to electrically connect the first inspection pad, the second inspection pad, and the third inspection pad. The circuit film includes a first line electrically connected to the first inspection pad, a second line electrically connected to the second inspection pad, a third line electrically connected to the third inspection pad, and a branch point configured to branch at least one line from the first line, the second line, and the third line into two sub-lines. The PCB includes a test pad unit connected to the first line, the second line, and the third line.

In an example, monitoring circuitry includes a first and a second coupling to electrically connect the monitoring circuitry to a monitored circuit having a resistance. The resistance of the monitored circuit may be indicative of a status, and the monitored circuit may be connected in series between the first and second coupling. The first coupling comprises a plurality of galvanically separated connection elements which are to form an electrical connection with a common connection element of the monitored circuit. The monitoring circuitry further comprises a monitoring apparatus to determine the resistance of the monitored circuit via the first coupling and the second coupling. The monitoring apparatus is to acquire a plurality of electrical values and to use the plurality of electrical values to determine a value of the resistance of the monitored circuit.

A method of remotely determining an impedance of an earth connection (142) of a first electrical equipment (122) connected to a power supply network (300). The method comprises receiving (606), from a first measurement node (302) connected to the first electrical equipment, a first value of an insulation impedance of the power supply network and receiving (612), from a second measurement node (304) connected to the power supply network, a second value of an insulation impedance of the power supply network. The method further comprises calculating (614) the impedance of the earth connection of the first electrical equipment using the first value of the insulation impedance of the power supply network, the second value of the insulation impedance of the power supply network and a known impedance value of an earth connection (144) of the second measurement node.

The present invention relates to a method for monitoring at least one electronic switching contact for a door system for a vehicle, wherein the switching contact has a first connection for a first electrical line and a second connection for a second electrical line. The method comprises a step of reading a first signal from a first monitoring point connected to the first connection in order to obtain a first monitoring signal, a step of reading a second signal from a second monitoring point connected to the second connection in order to obtain a second monitoring signal, and a step of combining the first monitoring signal and the second monitoring signal in order to determine at least one state of the at least one switching contact.

An anti-electrostatic wrist strap and a ground detection device are provided so as to prevent misjudgment resulted from a wrist strap wearer's skin being too dry. The wrist strap includes a resistor having resistance R connected between the wrist strap's two wires. Therefore a tolerance range is created when monitoring whether the wrist strip has an appropriate resistance. Similarly, the detection device includes a resistor having resistance R parallel-connected to its detection circuit to a wrist strap. A tolerance range is created when monitoring whether the wrist strip has an appropriate resistance. By the wrist strap or the detection device, the chance of misjudgment is effectively reduced. To further enhance electrostatic protection, the detection device includes a power provision interface and an electrical switch so that, only when the electrostatic leakage circuit has an appropriate resistance, the electrical switch enables the power provision interface to supply electricity to related apparatuses.

An anti-electrostatic wrist strap and a ground detection device are provided so as to prevent misjudgment resulted from a wrist strap wearer's skin being too dry. The wrist strap includes a resistor having resistance R connected between the wrist strap's two wires. Therefore a tolerance range is created when monitoring whether the wrist strip has an appropriate resistance. Similarly, the detection device includes a resistor having resistance R parallel-connected to its detection circuit to a wrist strap. A tolerance range is created when monitoring whether the wrist strip has an appropriate resistance. By the wrist strap or the detection device, the chance of misjudgment is effectively reduced. To further enhance electrostatic protection, the detection device includes a power provision interface and an electrical switch so that, only when the electrostatic leakage circuit has an appropriate resistance, the electrical switch enables the power provision interface to supply electricity to related apparatuses.

A diagnostic method for contact resistance failure includes estimating electrical contact surface resistance of at least one contactor, determining a faulted status of the at least one contactor and indicating the faulted status of the at least one contactor if the at least one contactor is in the faulted status.

The present method relates to a method for checking a multi-pole electrical circuit breaker. The multi-pole electrical circuit breaker comprises a plurality of poles (101-103). Each of the plurality of poles (101-103) comprises a first connection (121-123) and a second connection (131-133). Closing the particular pole (101-103) makes it possible to electrically connect the first connection (121-123) of the particular pole (101-103) to the second connection (131-133) of the particular pole (101-103) via the pole. In the method, a plurality of micro-ohm measurements are carried out at the plurality of poles (101-103), while the plurality of poles (101-103) are earthed on both sides in a P-P-P-E configuration. A contact resistance of one of the plurality of poles (101-103) is determined on the basis of the plurality of micro-ohm measurements.

The present method relates to a method for checking a multi-pole electrical circuit breaker. The multi-pole electrical circuit breaker comprises a plurality of poles (101-103). Each of the plurality of poles (101-103) comprises a first connection (121-123) and a second connection (131-133). Closing the particular pole (101-103) makes it possible to electrically connect the first connection (121-123) of the particular pole (101-103) to the second connection (131-133) of the particular pole (101-103) via the pole. In the method, a plurality of micro-ohm measurements are carried out at the plurality of poles (101-103), while the plurality of poles (101-103) are earthed on both sides in a P-P-P-E configuration. A contact resistance of one of the plurality of poles (101-103) is determined on the basis of the plurality of micro-ohm measurements.

A testing method for the sheet resistance and contact resistance of connecting point of a sheet material, comprising: mounting at least four small electrodes on the surface of the sheet material; measuring the resistance between the electrodes; and calculating the sheet resistance and electrode contact resistance of the sheet material on the basis of a theoretical model from the resistance measured between the electrodes and the distances between the electrodes. As a main feature, the testing method is a convenient nondestructive testing method for the sheet resistance and electrode contact resistance of the sheet material, and has no strict requirement on the distribution of electrodes.