This invention discloses a type of noncontact linear potentiometer; the potentiometer comprises a slider, a rotating shaft, a guide rod, a tunneling magnetoresistive sensor, a permanent magnet, a printed circuit board, and two support structures. In this configuration the slider moves along the guide rod and the rotating shaft, causing the rotation of the rotating shaft; the permanent magnet is attached to an end of the rotating shaft, and it therefore rotates as the shaft rotates. A tunneling magnetoresistive sensor is located adjacent to the permanent magnet, soldered onto a printed circuit board, and it is used to measure the angle of rotation of the permanent magnet. The guide rod constrains the sliding direction of the slider, and the two support structures are located at the opposite ends of the guide rod and rotating shaft, and they are used to support the rotating shaft and guide rod. Located between the slider and rotating shaft is a ball bearing, a pin and a leaf spring assembly. This potentiometer has several advantages, including a compact structure, easy fabrication, long service life, in addition to providing smooth slider motion that provides a pleasing user experience.

This invention discloses a type of noncontact linear potentiometer; the potentiometer comprises a slider, a rotating shaft, a guide rod, a tunneling magnetoresistive sensor, a permanent magnet, a printed circuit board, and two support structures. In this configuration the slider moves along the guide rod and the rotating shaft, causing the rotation of the rotating shaft; the permanent magnet is attached to an end of the rotating shaft, and it therefore rotates as the shaft rotates. A tunneling magnetoresistive sensor is located adjacent to the permanent magnet, soldered onto a printed circuit board, and it is used to measure the angle of rotation of the permanent magnet. The guide rod constrains the sliding direction of the slider, and the two support structures are located at the opposite ends of the guide rod and rotating shaft, and they are used to support the rotating shaft and guide rod. Located between the slider and rotating shaft is a ball bearing, a pin and a leaf spring assembly. This potentiometer has several advantages, including a compact structure, easy fabrication, long service life, in addition to providing smooth slider motion that provides a pleasing user experience.

A load testing apparatus includes: a resistance unit including a plurality of resistors adapted to receive power supply from a test target power source and a wall adapted to hold both ends of each of the plurality of resistors; and a cover attached to a frame holding the resistance unit and adapted to protect the wall and a portion included in a terminal of the resistor and projecting and exposed from the wall. Each of the resistors includes a cap. The cap has an insulation property and is attached to the portion included in the terminal and projecting from the wall. The cover is made of a conductive material. The cap is arranged between the cover and the portion included in the terminal and projecting from the wall.

A high-energy resistor has a resistive body comprising unbound particulate material. The resistance value of the resistor can be determined in part by a mixing ratio of components in the unbound particulate material and a pressure applied to the particulate material. For a selected mixing ratio, the resistance of the assembled resistor can be adjusted to obtain a selected resistance value with high accuracy by changing pressure on the unbound particulate material. Such adjustment can be made readily by a user before and/or after the resistor is installed in a system. The adjustment can be automated and made during operation of the system to maintain a resistance value precisely.

A high-energy resistor has a resistive body comprising unbound particulate material. The resistance value of the resistor can be determined in part by a mixing ratio of components in the unbound particulate material and a pressure applied to the particulate material. For a selected mixing ratio, the resistance of the assembled resistor can be adjusted to obtain a selected resistance value with high accuracy by changing pressure on the unbound particulate material. Such adjustment can be made readily by a user before and/or after the resistor is installed in a system. The adjustment can be automated and made during operation of the system to maintain a resistance value precisely.

A rotary position sensor for measuring the position of a rotating shaft comprises an upper housing and a lower housing arranged to be attached to the upper housing. A barrel is rotationally mounted to the attached upper and lower housings and coupled to the shaft is arranged to be positionable within the attached upper and lower housings by the shaft. A potentiometer component is mounted to the barrel and to an electrical sub-assembly that measures the position of the barrel and in response generates a position signal.

A rotary position sensor for measuring the position of a rotating shaft comprises an upper housing and a lower housing arranged to be attached to the upper housing. A barrel is rotationally mounted to the attached upper and lower housings and coupled to the shaft is arranged to be positionable within the attached upper and lower housings by the shaft. A potentiometer component is mounted to the barrel and to an electrical sub-assembly that measures the position of the barrel and in response generates a position signal.

A resistor trimming device comprising a resistor trimming unit is provided, which divides a single one adjustable resistor string into a plurality of adjustable resistor string groups, so that a resistance of the parallel resistor faced by a switch can be effectively reduced, and a design of the on-resistance and off-resistance of the switch can comply with a general design rule. In addition, the resistor trimming device provided further comprises a decoder. When trimming the overall resistance of an electronic device, a user can directly input a binary code or an original thermometer code used in the adjustable resistor string being not grouped, without knowing an encoding manner, and then, the decoder generates a trimming thermometer code and a group code to control a main switch and switches in the multiple adjustable resistor string groups being the grouped from the adjustable resistor string.

A resistor trimming device comprising a resistor trimming unit is provided, which divides a single one adjustable resistor string into a plurality of adjustable resistor string groups, so that a resistance of the parallel resistor faced by a switch can be effectively reduced, and a design of the on-resistance and off-resistance of the switch can comply with a general design rule. In addition, the resistor trimming device provided further comprises a decoder. When trimming the overall resistance of an electronic device, a user can directly input a binary code or an original thermometer code used in the adjustable resistor string being not grouped, without knowing an encoding manner, and then, the decoder generates a trimming thermometer code and a group code to control a main switch and switches in the multiple adjustable resistor string groups being the grouped from the adjustable resistor string.