A variable resistor includes: a main body and a rotating part vertically separated away from each other, among which the main body includes: a substrate having a first main surface, a second main surface and a through hole vertically penetrating the first main surface and the second main surface; a first conductive portion and a second conductive portion provided on the first main surface; a resistor body connected thereto; an electrode positioned closer to the through hole than the resistor body; and a third conductive portion (i) provided on each of the second main surface and a partition wall surface for partitioning the through hole and (ii) connected to the electrode, and the rotating part includes: an opposing part rotatable in a circumferential direction; and a slider configured to conductively slide as the rotating part rotates.

A variable resistor includes: a main body and a rotating part vertically separated away from each other, among which the main body includes: a substrate having a first main surface, a second main surface and a through hole vertically penetrating the first main surface and the second main surface; a first conductive portion and a second conductive portion provided on the first main surface; a resistor body connected thereto; an electrode positioned closer to the through hole than the resistor body; and a third conductive portion (i) provided on each of the second main surface and a partition wall surface for partitioning the through hole and (ii) connected to the electrode, and the rotating part includes: an opposing part rotatable in a circumferential direction; and a slider configured to conductively slide as the rotating part rotates.

A variable resistor according to the present invention includes a substrate, a resistive element disposed on a first surface of the substrate, oil that coats an upper surface of the resistive element, and a slide member that slides on the upper surface of the resistive element coated with the oil, wherein an output of the variable registor changes as a position at which the slide member makes contact with the resistive element changes. The variable resistor further includes an oil repellent part that surrounds at least a part of the resistive element in plan view viewed from above the first surface of the substrate, the oil repellant part having surface free energy smaller than that of the resistive element, whereby oil can be stably held on a resistive element surface without forming irregularities on the resistive element surface.

A variable resistor according to the present invention includes a substrate, a resistive element disposed on a first surface of the substrate, oil that coats an upper surface of the resistive element, and a slide member that slides on the upper surface of the resistive element coated with the oil, wherein an output of the variable registor changes as a position at which the slide member makes contact with the resistive element changes. The variable resistor further includes an oil repellent part that surrounds at least a part of the resistive element in plan view viewed from above the first surface of the substrate, the oil repellant part having surface free energy smaller than that of the resistive element, whereby oil can be stably held on a resistive element surface without forming irregularities on the resistive element surface.

An electronic device having a digitally controlled resistor is provided. The digitally controlled resistor includes various switch-resistor segments between voltage nodes. In one embodiment, the switch-resistor segment may include a resistor and a switch coupled parallel to the resistor. In another embodiment, the switch-resistor segment may include a resistor, a complement switch coupled in series with the resistor, and a switch coupled parallel to the resistor and the complement switch. Each switch included in the switch-resistor segment operates based on digital bits. Based on the logic value (either ‘0’ or ‘1’) assigned, the switches turn ON (when logic value is ‘1’) and OFF (when logic value is ‘0’). In some embodiments, the switches and the resistor included in the switch-transistor segment are arranged in a symmetrical manner between voltage nodes.

An electronic device having a digitally controlled resistor is provided. The digitally controlled resistor includes various switch-resistor segments between voltage nodes. In one embodiment, the switch-resistor segment may include a resistor and a switch coupled parallel to the resistor. In another embodiment, the switch-resistor segment may include a resistor, a complement switch coupled in series with the resistor, and a switch coupled parallel to the resistor and the complement switch. Each switch included in the switch-resistor segment operates based on digital bits. Based on the logic value (either ‘0’ or ‘1’) assigned, the switches turn ON (when logic value is ‘1’) and OFF (when logic value is ‘0’). In some embodiments, the switches and the resistor included in the switch-transistor segment are arranged in a symmetrical manner between voltage nodes.

A liquid level sensor includes a liquid level responsive member that moves in response to changing liquid level, an electrically conductive contact associated with the liquid level responsive member, a circuit including a rectifying element and a) one or more conductive elements, or b) one or more resistive elements or c) one or more conductive elements and one or more resistive elements, wherein the contact is arranged to engage at least one of the elements in a, b, or c, and a power supply. The power supply is adapted to provide a voltage to the circuit causing a current flow in a first direction in the circuit wherein the current flows through the contact and to provide a current flow in a second direction in the circuit wherein the rectifying element prevents current flow through the contact.

A liquid level sensor includes a liquid level responsive member that moves in response to changing liquid level, an electrically conductive contact associated with the liquid level responsive member, a circuit including a rectifying element and a) one or more conductive elements, or b) one or more resistive elements or c) one or more conductive elements and one or more resistive elements, wherein the contact is arranged to engage at least one of the elements in a, b, or c, and a power supply. The power supply is adapted to provide a voltage to the circuit causing a current flow in a first direction in the circuit wherein the current flows through the contact and to provide a current flow in a second direction in the circuit wherein the rectifying element prevents current flow through the contact.

A single turn potentiometer sensor has a substrate, a first and a second carbon print. The first carbon print, with a desired width, extends across a large circumferential angle. Ends of the carbon print are connected to a regulated power supply and ground. The second carbon print, with a width smaller than the first carbon print, surrounds a hole in the substrate and is positioned inside the first carbon print. The second carbon print provides a sensor output. A wiper contacts between the first and second carbon prints. A voltage divider changes value based on a wiper position on the first carbon print. One or more pads are positioned on the first carbon print. The one or more pads provides an input voltage to the sensor.

A single turn potentiometer sensor has a substrate, a first and a second carbon print. The first carbon print, with a desired width, extends across a large circumferential angle. Ends of the carbon print are connected to a regulated power supply and ground. The second carbon print, with a width smaller than the first carbon print, surrounds a hole in the substrate and is positioned inside the first carbon print. The second carbon print provides a sensor output. A wiper contacts between the first and second carbon prints. A voltage divider changes value based on a wiper position on the first carbon print. One or more pads are positioned on the first carbon print. The one or more pads provides an input voltage to the sensor.