The symbol of the variable resistor is R and the unit is ohm.
Variable resistor is a kind of resistance, it can play the role of resistance in electronic circuits. The difference between it and general resistance is that its resistance can be continuously changed within a certain range. In some cases, the resistance value changes but not often. Variable resistors can be used for changing occasions.
The variable resistor is an adjustable electronic component. It is composed of a resistor body and a rotating or sliding system. The variable resistor is a variable resistor used for voltage division. It is usually used in circuits that need to adjust the resistance frequently, and plays the role of adjusting voltage, adjusting current or signal control, and its main parameters are basically the same as fixed resistors.
Variable resistor appearance characteristics(1) The volume of the variable resistor is larger than that of the general resistor, and there are fewer variable resistors in the circuit, which can be easily found on the circuit board.
(2) There are three pins in the variable resistor. The three pins are different. One is the movable pin and the other two are the fixed pins. Generally, the two fixed pins can be used interchangeably. The pins of the fixed and movable plates cannot be used interchangeably.
(3) There is an adjustment port on the variable resistor. Use a flat-blade screwdriver to reach into this adjustment port. Turn the screwdriver to change the position of the moving piece and adjust the resistance.
(4) The nominal resistance value can be seen on the variable resistor. This nominal resistance value refers to the resistance value between two stator pins, which is also a certain stator pin and a moving piece pin. The maximum resistance between.
(5) Vertical variable resistors are mainly used in small signal circuits. Its three pins are vertically downward and mounted on the circuit board vertically, and the resistance adjustment port is in the horizontal direction.
(6) Horizontal variable resistors are also used in small signal circuits. Its three pins are at 90° to the resistance plane, vertically downward, and installed on the circuit board horizontally, with the resistance adjusting port facing upward.
(7) The variable resistor of the small plastic case has a smaller volume and a circular structure. Its three pins are downward and the resistance adjustment port faces upward.
(8) The variable resistor (wire-wound structure) used in the occasion of high power has a large volume, and the movable piece can slide left and right to adjust the resistance value.
Variable resistor circuit symbol
As shown in the figure above, it is the symbol of the variable resistor circuit. The variable resistor circuit symbol uses an arrow on the basis of the common resistor circuit symbol to visually indicate its variable resistance characteristics. Two fixed pin and one moving pin can be identified from the circuit symbol. This is the latest variable resistor circuit symbol specified by the national standard, and the letters in RP represent variable resistors.
A large number of existing circuit diagrams do not use this circuit symbol, but use the old circuit symbol as shown in Figure (a). This symbol vividly represents the principle of variable resistor resistance adjustment and the actual connection in the circuit. Happening. Its moving piece pin is connected to a fixed piece pin, so that a part of the resistance in the resistor body is short-circuited, and the resistance of the variable resistor is the resistance of the resistor body between the moving piece pin and the other fixed piece bow leg. value. The variable resistor in Figure (a) only uses two pins.
Picture (b) shows the circuit symbol when the variable resistor is used as a potentiometer. It is obviously different from the picture (a). Its three pins are independent. This is how to use the potentiometer of the variable resistor. .
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