Mumbai University > Electronics Engineering > Sem3 > Electronic Instruments and Measurements

Marks: 10M

Year: June 2015

To learn about a capacitive transducer, it is important to know the basics of a parallel plate capacitor.

• Being the simplest form of a capacitor, it has two parallel conducting plates that are separated by a dielectric or insulator with a permittivity of Ε (for air). Other than paper, vacuum, and semi-conductor depletion region, the most commonly used dielectric is air.

• Due to a potential difference across the conductors, an electric field develops across the insulator. This causes the positive charges to accumulate on one plate and the negative charges to accumulate on the other.

• The capacitor value is usually denoted by its capacitance, which is measured in Farads. It can be defined as the ratio of the electric charge on each conductor to the voltage difference between them.

Advantages –

• It produces an accurate frequency response to both static and dynamic measurements

Disadvantages –

• An increase or decrease in temperature to a high level will change the accuracy of the device

• As the lead is lengthy it can cause errors or distortion in signals.