Variable resistors are typically manufactured in a configuration in which a resistive element is terminated in at least one fixed terminal. A moveable terminal is attached to an actuator, such as a rotary knob, thumbwheel, or slideable member, such that the moveable terminal contacts different regions of the resistive element as a user manipulates the actuator. Generally, a variable resistor comprises a case having a concavity, a resistor substrate having a resistor formed on the surface thereof and disposed on the bottom of the concavity of the case,.and a rotor having a slider fixed to the underside thereof and received rotatably in the concavity of the case. A typical variable resistor assembly has a wiper mechanically movable across contact segments of a resistor to change resistance value without interrupting a circuit to which the resistor is connected. The resistance can be changed by sliding the slider on the resistor of the resistor substrate. A resistor used for a variable resistor of various sensors contains resin serving as based material of the resistor, carbon fiber serving as structural material, and carbon black serving as conducting particle, and a slider moves in contact with a resistor pattern consisting of the resistor. Carbon film type variable resistors have been generally extensively utilized as variable resistors for use in radio receivers, audio amplifiers and TV receivers. Carbon film type variable resistors are roughly divided into rotary types and sliding types. A variable resistor preferably comprises a stopper mechanism for preventing breakage resulting from overrotation, since the position of a slider cannot be visually confirmed in adjustment of resistance. Variable resistors that include a switch are generally rotary actuated where the operating shaft of the switch is movable in the axial direction with one end projecting from the body of variable resistor switch.

A rotary variable resistor with switch is characterized by having two mechanisms, namely, the variable resistance mechanism for varying the resistance value, and the switch mechanism for electric contact and non-contact by on/off operation of the switch. Rotary variable resistors with an annular cross section are commonly used as equipment controls. The increasing sophistication of equipment and the trend for centralization of operating units have led to building switches and other electronic components into rotary variable resistors and mounting them on equipment wiring boards. A high-voltage variable resistor commonly called a focus pack is capable of variably outputting a focus voltage and a screen voltage. In general, a high-voltage variable resistor unit is mounted on a transformer casing of a flyback transformer. A high-voltage variable resistor unit of which an applied voltage is decreased is conventionally constructed in such a manner that a variable resistance circuit pattern for a variable resistance and a fixed resistance circuit pattern for a fixed resistance called a bleeder resistance which is connected in series to the variable resistance circuit pattern are formed on a single insulating substrate. In recent years, there has been the general tendency that apparatuses or equipment is generally miniaturized and small-sized, and the reduction in the size and the weight of the circuit components provided within such electronic equipment has also been desired. Accordingly, the miniaturization of variable resistors is required.