Understanding LVDT Full Form

The question asks for the long form, or full form, of the abbreviation LVDT. LVDT is a common type of sensor used in various applications.

The full form of LVDT is Linear Variable Differential Transformer.

Let's break down the name to understand what an LVDT is:

• Linear: This indicates that the device is used to measure displacement along a straight line. It measures linear motion.
• Variable: The output of the device changes variably in proportion to the displacement being measured.
• Differential: The device works by comparing the voltage output from two secondary coils, which are connected in a differential manner.
• Transformer: This refers to the core principle of operation. An LVDT is a type of electrical transformer where a movable core alters the magnetic coupling between coils.

Therefore, an LVDT is a sensor that measures linear displacement using the principle of a differential transformer where the output voltage varies depending on the position of a movable core.

Analyzing the Options

Let's look at the given options:

• Option 1: Linear Voltage Defined Transformer - This is incorrect. "Voltage Defined" is not part of the standard abbreviation.
• Option 2: Linear Variable Differential Transformer - This matches the correct full form.
• Option 3: Low Voltage Differential Transducer - This is incorrect. While LVDTs can be transducers and might operate at relatively low voltages, "Low Voltage" and "Transducer" are not the standard terms in the LVDT abbreviation.
• Option 4: Low Variable Defined Transducer - This is incorrect. Neither "Low Variable" nor "Defined Transducer" accurately represents the terms in LVDT.

Based on the standard definition, the correct expansion is Linear Variable Differential Transformer.

Revision Table: LVDT Full Form

Additional Information: LVDT Working Principle and Applications

An LVDT typically consists of a primary coil and two secondary coils wound on a hollow cylindrical form. A movable core slides within this form. The primary coil is excited by an AC voltage.

When the core is exactly in the center position (null position), the voltage induced in the two secondary coils is equal but 180 degrees out of phase. When the secondary coils are connected in series opposition, the net output voltage is zero at the null position.

As the core moves away from the null position in one direction, the coupling to one secondary coil increases while the coupling to the other decreases. This results in a differential voltage output proportional to the displacement and with a phase that indicates the direction of motion.

LVDTs are widely used for measuring displacement in various applications, including:

• Industrial automation
• Aerospace (e.g., flight control surfaces)
• Hydraulics and pneumatics
• Structural monitoring
• Medical devices
• Quality control and inspection

Their advantages include high accuracy, repeatability, frictionless operation, and long operational life.