Potentiomters ( POT)

Potentiometers

·         A potentiometer is generally used to measure linear or angular displacement.

·         A resistive potentiometer consists of a wire wound resistive element along with a sliding contact which is called wiper. The diameter of the wire is about 0.01 mm and the resistive element is made up of cement, hot moulded carbon or carbon flim. The wire is wound on insulating former.

·         Using resistive potentiometer mechanical displacement is converted into an electrical voltage or current. Linear or angular displacement is applied to sliding contact and the corresponding change in resistance is converted into voltage or current.

·         To measure combination of linear and angular displacement helipots used.

Advantages:

·         Simple construction and operation

·         Inexpensive

·         Useful for displacement measurements of large amplitudes

·         High electrical efficiency

Disadvantages:

·         A huge force may be required for the slider movement.

·         Can produce unwanted noise due to alignment problems, wear and tear of the sliding contact. This may also affect the total life of the device.

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Classification of transducers

Classification of transducers

1.      Based on the physical phenomenon,

·         Primary transducer   

·          Secondary transducer

2.      Based on the power type Classification,

·         Active transducer

·         Passive transducer

3.      Based on the type of output the classification of transducers are made,

·         Analog transducer

·         Digital transducer

4.      Based on the electrical phenomenon is a best Classification of Transducer,

·         Resistive transducer

·         Capacitive transducer

·          Inductive transducer

·          Photoelectric transducer

·         Photovoltaic transducer

5.      Based on the non-electrical phenomenon Classification of transducer,

·         Linear displacement

·         Rotary displacement

6.      Based on the transduction phenomenon,

·         Transducer

·         Inverse transducer.

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How Capacitor microphone works ?

Capacitor microphone

·         A condenser microphone is a microphone that uses a capacitor to convert the compression and rarefaction of sound waves into electrical energy.

·         A condenser microphone works by using a capacitor to convert the compression and rarefaction of sound waves into electrical energy.  A capacitor is a passive electronic component consisting of two conductors separated by a dielectric (insulator).  This capacitor within the condenser microphone is referred to as a “capsule”. 

·          A condenser microphone capsule consists of a front plate made out of a thin, flexible, metalized material (referred to as the diaphragm or membrane) and a back plate made out of a solid metal material, as well as a thin dielectric separating the two conductors. Voltage is sent to the capsule in order to create a charge within the capsule.  This voltage is known as “phantom power”.

·          When the diaphragm is struck by sound waves, it causes the diaphragm to vibrate, which, in turn causes a change in capacitance within the capsule.  As the capacitance changes, it creates a change in voltage.  This electrical signal is then sent via wires to an internal amplifier, then to the microphones output.

                                                       

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