Which potentiometer to choose

What potentiometer should I choose? Ask Question. Asked 8 years, 11 months ago. Active 4 years, 7 months ago. Viewed 14k times. So I need a potentiometer, with a knob since I'm going to create a casing for it all : Also, I'm planning in stereo, so that's 2x LM but I don't want two volume controls. Jason94 Jason94 2 2 gold badges 7 7 silver badges 16 16 bronze badges.

Add a comment. Active Oldest Votes. Okay, here are some images related to pot impedance. Kaz Kaz But where do I get "dual ganged potentiometer".

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Check the power rating. Make sure your potentiometer is rated for your circuit's current and voltage. If you find a seemingly perfect potentiometer for a bass guitar amplifier, make sure it can handle the power going through it. Select the appropriate tolerance.

Like all resistors, real world potentiometers will vary from their design by a given tolerance. This is no big deal for a bass guitar amplifier, but it might matter if you're controlling a more refined signal, such as a thermostat in your home. How to Choose a Potentiometer. Related Articles How to Use a Variac. How to Read Ohms on a Ranged Multimeter. How to Adjust Electrical Amperage. How to Connect an Ammeter. It is mostly used as a voltage divider when the potentiometer is a four-terminal element.

The potentiometer is basically a sliding rheostat. There are several types of potentiometers, which are generally used to adjust the power of the loudspeaker volume switch and laser head. The potentiometer is an adjustable electronic component. The rheostat is used for voltage division.

On the exposed resistor body, one or two movable metal contacts are pressed. The contact position determines the resistance between the two ends of the resistor and the contact.

According to material branch winding, carbon film, solid potentiometer; according to the relationship between the output and input voltage ratio and the rotation angle, linear potentiometer linear relationship , function potentiometer in a curve relationship.

The main parameters are resistance, tolerance, and rated power. It is widely used in electronic equipment for audio and receiver volume control. The main parameters of the potentiometer include nominal resistance, rated power, resolution, sliding noise, zero resistance and temperature coefficient, etc.

The high-precision potentiometer error only has 0. And it can be in any functional form, commonly used are linear, logarithmic and reverse logarithmic exponential. It is expressed as the percentage of the total voltage added to the maximum deviation between the actual characteristics and the theoretical characteristics, which can represent the accuracy of the potentiometer. For wirewound potentiometer and linear potentiometer, the resolution is expressed as a percentage of the total resistance and changing resistance caused by each turn of the moving contact on the winding.

For potentiometers with functional characteristics, because the resistance of each turn on the winding is different, the resolution is a variable. When changing the resistance, due to improper distribution of potentiometer resistance, improper coordination of the rotating system, and contact resistance of the potentiometer, when the movable contact moves on the surface of the resistor, useful signals are accompanied by fluctuating noise signals.

For wirewound potentiometer, in addition to the above-mentioned contact noise between the moving contact and the winding, there are also resolution noise and short-circuit noise. The resolution noise is caused by the stepped nature of the resistance change, while the short-circuit noise is generated when the moving contact moves on the winding and shorts adjacent turns. It is related to the current flowing through the winding and the turns.

The resistance and the contact resistance between the moving contact and the winding are proportional. It refers to the total number of reliable movements of the contact under the specified test conditions, which is related to the type, structure, material and manufacturing process of the potentiometer.

In addition to the above-mentioned characteristic parameters, the potentiometer also has parameters such as, allowable resistance deviation, maximum working voltage, rated working voltage, insulation voltage, temperature parameters, noise electromotive force and high-frequency characteristics. The meaning of these parameters corresponds to that of resistors. In addition to the nominal resistance and rated power, the main parameters of the potentiometer also have a resistance change characteristic, which refers to the relationship between the resistance value and the rotation angle or sliding stroke of the boom.

Common potentiometer resistance changes are linear X-type , exponential Z-type , and logarithmic D-type. The curve of the three types of potentiometer resistance as a function of the angle of rotation of the movable contact is shown in Figure 1.

The ordinate in the figure represents the actual value of the resistance at a certain angle and the percentage of the total resistance of the potentiometer. The abscissa is the percentage of the rotation angle and the maximum rotation angle.

The resistance change of the X-type potentiometer is linear with the rotation angle. That is, the distribution of the conductive material on the resistor body is uniform, so the resistance per unit length is equal. It is suitable for some applications that require uniform adjustments, such as voltage dividers, bias current adjustment and other circuits. When the Z-type potentiometer starts to rotate, the resistance value changes little, and when the rotation angle approaches one end of the maximum rotation angle, the resistance value changes more obviously.

Because the human ear has a slight increase in the tiny sound, it feels very sensitive, but after the sound reaches a certain value, even if the sound power is greatly increased, the feeling of the human ear does not change much. This potentiometer is suitable for the volume control circuit because the potentiometer is used for volume control, the relationship between the volume and the potentiometer angle is approximately linear.

The resistance change of the D-type potentiometer is opposite to that of the Z-type. The resistance value changes greatly when it starts to rotate, and the resistance value changes slowly when the rotation angle approaches the maximum value. The D-type potentiometer is suitable for circuits such as tone control. Figure 1. Resistance Change Characteristic Curve.

If the potentiometer has a slight contact failure, pure alcohol can be used to clean the contact between the carbon film and the movable part; if the carbon film is severely worn in the potentiometer and the contact is poor, you can gently bend the metal contact inward or outward to change the trajectory of the metal brush on the carbon film; if the potentiometer has a certain piece of film and the carbon film open circuit mostly open in the silver plating layer , and does not use another fixed or movable block to be welded together, then the welding parts of the two fixed parts can be exchanged, and it can still be used normally.

For example, the potentiometer A stator and the carbon film are broken, at this time, potentiometer A can be soldered and the B-slice can be replaced. If the carbon film is worn, use a pencil to apply the carbon on it to maintain its use. If it is severely damaged or the conditions permit, it will be replaced as much as possible.

It is the most used potentiometer at present. The resistor body is made of a mixture of carbon black, graphite, quartz powder, organic binder, etc. Variety: Common synthetic carbon film potentiometer, small synthetic carbon film potentiometer with switch, single-band switch no switch potentiometer, double coaxial no switch with switch potentiometer, double-axis without switch With switch potentiometer, small precision synthetic carbon film potentiometer, push-pull switch synthetic carbon film potentiometer, straight-slip synthetic carbon film potentiometer, precision multi-turn synthetic carbon film potentiometer.

The resistor body is made of a wire wound around a metal or non-metal plate coated with an insulating material. Advantages: high power, low noise, high precision and good stability;.

Disadvantages: Poor high-frequency characteristics. The resistor body is made by depositing a metal alloy film, a metal oxide film, a metal composite film, and a ruthenium oxide film material on a ceramic substrate by a vacuum technique.

Advantages: high resolution, sliding noise is smaller than synthetic carbon film potentiometer;. Disadvantages: small resistance range and poor wear resistance. The resistor body is a rectangular strip, which changes the resistance value by linear movement of the slider connected to the slider.

Usage: Generally used for volume control or equalization control in TV sets and stereos. Single-turn potentiometer: its sliding arm can only rotate within less than degrees, generally used for volume control;. Multi-turn potentiometer: For every revolution of its rotating shaft, the sliding arm contact changes only a small distance on the resistor body. When the sliding arm is from one extreme position to the other extreme position, the rotating shaft needs to rotate a plurality of turns.

Generally used in precision adjustment circuits. It is made by mixing materials heated with carbon black, graphite, quartz powder, organic binder, etc. Single potentiometer: a set of potentiometers controlled by a separate shaft. Double potentiometer: Usually two potentiometers with the same specifications are mounted on the same shaft.

When the shaft is adjusted, the sliding contacts of the two potentiometers rotate synchronously, which is suitable for the volume adjustment of the two-channel stereo amplifier circuit.

There are also some double-connected potentiometers that are asynchronous. It consists of a stepping motor, rotating shaft resistor, moving contact and so on. The moving contacts can be manually adjusted by a rotating shaft or driven by a stepping motor. Purpose: Used for volume control in the audio power amplifier. A switching device is attached to the potentiometer. The switch and potentiometer are coaxial. The movement and control mode of the switch can be divided into two types: rotary type and push-pull type.

Purpose: It is mostly used for volume control and power switch in black and white TV sets. A small rotary switched potentiometer is mainly used for volume control or current and voltage regulation and power switch in semiconductor radio or other small electronic products.

Types: Switching digits are single-pole single-throw, single-pole double-throw and double-pole single-throw. It is also known as a sheet potentiometer, which is a miniature linear potentiometer without a manual rotating axis. A screwdriver and other tools are needed for adjustment.