Patent ID: 7583177

Claim:
A variable resistor comprising: a casing having an open end a substrate being mounted on the open end of the casing and having a front surface; a rear surface; a through hole; and a terminal group being conductive and formed on the front surface of the substrate and having a first terminal having an annular segment surrounding the through hole and a connector extending from the annular segment; a second terminal being separated from the first terminal and having a connector adjacent to the connector of the first terminal; and a third terminal being separated from the first terminal and the second terminal and having a semi-circular segment being disposed adjacent to the annular segment of the first terminal and having a proximal end and distal end; and a connector extending from the proximal end of the semi-circular segment adjacent to the terminal of the second terminal; an insulating film being annular, covering the second terminal and the semi-circular segment of the third terminal, surrounding the annular segment and having a central hole corresponding to the annular segment of the first terminal; and two gaps respectively corresponding to the second terminal and the distal end of the semi-circular segment of the third terminal; a resistance element being annular, being mounted correspondingly on the insulating film and respectively contacting the second terminal and the distal end of the semi-circular segment of the third terminal through the gaps of the insulating film; a rotary assembly being mounted on the substrate and attached to the casing; and a wiper being attached to and rotated by the rotary assembly and having multiple first contacts contacting the resistance element; and multiple second contacts contacting the annular segment of the first terminal of the terminal group.