Sliding rheostat

The resistance wire is wound into a coil, and the length of the resistance wire connected to the circuit is changed by sliding the sliding sheet, thereby changing the resistance value.

The composition of the sliding rheostat, note: 1. terminal; 2. sliding sheet; 3. resistance wire brushed with insulating paint; 4. metal rod; 5. cylinder made of porcelain or other insulators.

When connecting the circuit, it is generally connected in series and connected "one up and down", which is called current-limiting connection.

There is also a connection method to connect three terminals, "two-one-one-up" connection, which becomes a partial pressure connection. This kind of connection will consume a lot of power, except for unavoidable circumstances, this connection is generally not used.

Resistance box

The sliding rheostat can change the resistance of the connected circuit and play the role of continuously changing the current, but it cannot accurately know the resistance of the connected circuit. If you need to know the resistance of the resistor connected to the circuit, you need to use a resistance box.

The resistance box is a rheostat that can adjust the size of the resistance and display the resistance value.

Compared with a sliding rheostat, a sliding rheostat cannot indicate the resistance value of the connected circuit, but it can continuously change the resistance in the connected circuit. The resistance box can indicate the resistance value connected to the circuit, but the resistance value change is discontinuous, and there is no accurate change in the value of the sliding rheostat.

Potentiometer

The potentiometer is a kind of adjustable resistance. It is usually composed of a resistor body and a rotating or sliding system, that is, a movable contact moves on the resistor body to obtain part of the voltage output.

The role of the potentiometer-adjust the voltage (including DC voltage and signal voltage) and the size of the current.

The structural characteristics of the potentiometer-the resistor body of the potentiometer has two fixed ends. By manually adjusting the shaft or sliding handle, changing the position of the movable contact on the resistor body will change the position between the movable contact and any fixed end. The resistance value, which changes the size of the voltage and current.

The potentiometer is an adjustable electronic component. It is composed of a resistor body and a rotating or sliding system. When a voltage is applied between the two fixed contacts of the resistor body, the position of the contact on the resistor body is changed by rotating or sliding the system, and a moving contact position can be obtained between the movable contact and the fixed contact The voltage of a certain relationship. It is mostly used as a voltage divider, at this time the potentiometer is a four-terminal element. The potentiometer is basically a sliding rheostat. There are several styles of potentiometers (as shown in the picture). The potentiometer generally used in the volume switch of the speaker and the power adjustment of the laser head is an adjustable electronic component. It is composed of a resistor body and a rotating or sliding system. A variable resistor used to divide the voltage when a voltage is applied between two fixed electric shocks of the resistor body. On the bare resistor body, one or two movable metal contacts are pressed tightly. The position of the contact determines the resistance between either end of the resistor and the contact. According to the material, it is divided into wire-wound, carbon film, solid core potentiometer; according to the relationship between the output and input voltage ratio and the rotation angle, it is divided into linear potentiometer (in a linear relationship) and function potentiometer (in a curve relationship). The main parameters are resistance, tolerance, and rated power. It is widely used in electronic equipment and used for volume control in speakers and receivers. Therefore, adjustable resistors can also be used frequently in daily life.