Potentiometer and Types of Potentiometer

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Hello everybody, welcome to instrumentation Training channel • In my Previous video I discussed regarding Thermistor, it’s working principle and types of thermistor , link for this is given in the description below • • What is Thermistor, It's Operation an... • In todays video I am gonna discuss Potentiometer, it’s operation and types of Potentiometers which is very important in learning basic instrumentation • Now we will know what is Potentiometer and it’s working • Potentiometer also known as pot is generally used in circuits to provide variable resistance or variable voltage. Thats why this is also called as variable Resistor. The heart of the potentiometer is a resistive strip inside it through which one can adjust the amount of resistance/voltage to pass in a circuit through it. • Potentiometers are commonly used in circuits for various purposes like to control volume in audio circuits, to regulate the speed of the motor in a fan, as light dimmer, etc. • A potentiometer is an instrument for measuring the potential (voltage) in a circuit. Before the introduction of the moving coil and digital volt meters,potentiometers were used in measuring voltage, hence the ‘-meter’ part of their name. • Now we will know different types of Potentiometer • There are two main types of potentiometers: • Rotary potentiometer • Linear potentiometer • Although the basic constructional features of these potentiometers vary, the working principle of both of these types of potentiometers is the same. • Note that these are types of DC potentiometers – the types of AC potentiometers are slightly different. • First one Rotary Potentiometers • The rotary type potentiometers are used mainly for obtaining adjustable supply voltage to a part of electronic circuits and electrical circuits. The volume controller of a radio transistor is a popular example of a rotary potentiometer where the rotary knob of the potentiometer controls the supply to the amplifier. • This type of potentiometer has two terminal contacts between which a uniform resistance is placed in a semi-circular pattern. The device also has a middle terminal which is connected to the resistance through a sliding contact attached with a rotary knob. By rotating the knob one can move the sliding contact on the semi-circular resistance. The voltage is taken between a resistance end contact and the sliding contact. The potentiometer is also named as the POT in short. POT is also used in substation battery chargers to adjust the charging voltage of a battery. There are many more uses of rotary type potentiometer where smooth voltage control is required. • Second one Linear Potentiometers • The linear potentiometer is basically the same but the only difference is that here instead of rotary movement the sliding contact gets moved on the resistor linearly. Here two ends of a straight resistor are connected across the source voltage. A sliding contact can be slide on the resistor through a track attached along with the resistor. The terminal connected to the sliding is connected to one end of the output circuit and one of the terminals of the resistor is connected to the other end of the output circuit.it wasn learnt by class 12 th • This type of potentiometer is mainly used to measure the voltage across a branch of a circuit, for measuring the internal resistance of a battery cell, for comparing a battery cell with a standard cell. • Digital Potentiometers • Digital potentiometers are three-terminal devices, two fixed end terminals and one wiper terminal which is used to vary the output voltage. • Digital potentiometers have various applications, including calibrating a system, adjusting offset voltage, tuning filters, controlling screen brightness, and controlling sound volume. However mechanical potentiometers suffer from some serious disadvantages which make it unsuitable for applications where precision is required. Size, wiper contamination, mechanical wear, resistance drift, sensitivity to vibration, humidity, etc. • Low-cost instrument. • It can be operated easily. • It provides accurate results. • And now Disadvantages of Potentiometer • Though the operation is quite simple but sometimes due to environmental effects the jockey creates problem while moving. • External factors sometimes hinder the accuracy of producing the results • Also Applications of Potentiometers • The potentiometer can be worked as a voltage divider to obtain a manual adjustable output voltage at the slider from a fixed input voltage applied across the two ends of the potentiometer. • Audio Control: Sliding potentiometers, one of the most common uses for modern low-power potentiometers are as audio control devices • Television: Potentiometers were used to control the picture brightness, contrast, and colour response. • One of the most common application is measuring of displacement. To measure the displacement of the body, which is movable, is connected to the sliding element located on the potentiometer.

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