What is absolute humidity? Basically absolute means real value. It is the amount of water contained in a given mass of air at a given temperature. This means you can accurately detect the humidity in the air. Air density is an important criterion for determining absolute humidity. Absolute humidity (AH) is mathematically defined as AH = water vapor/air ratio.

What is a Shell Type Transformer? Basically a shell type transformer is one in which the core of the transformer surrounds the windings. And in this type of transformer, the core surrounds the primary and secondary windings. Therefore, they are called shell type transformers. Both the windings are wound on the central limb of the core. As you can see, the circuit has two flux paths. The central organ carries the entire magnetic flux; and the other two side limbs carry half of the flow. HV and LV winding mounting is same as discussed earlier in core type transformer. In the second image below, the red winding is the primary and the green winding is the secondary.

What is a core type transformer? Basically a core type transformer is one in which primary and secondary windings surround the transformer core. And transformers have two types of windings basically primary and secondary. The voltage is transferred from the primary to the secondary winding through the magnetic flux. And the core is the layer of metal that conducts the magnetic field and can also be called the main body of the transformer. So, in this type of transformer, windings surround the core. Hence, they are called core type transformers. The part which is twisted is also known as the limb. Both the windings are mounted on separate limbs of the core. And core type transformers have only single flux path in the circuit. Also, it is worth noting that there are two types of windings on each of the primary and secondary - low voltage (LV) and high voltage (HV). In the image below, green color is LV winding and red color is HV winding. The LV winding is placed near the core and the HV

How does solar energy work? Frame, glass, front adhesive film, solar cell, back adhesive film, back sheet and junction box are the primary components of a complete panel. The main component here is the solar cell. It is also known as photovoltaic cell. When solar energy hits it, it generates electricity; This is called Photovoltaic Effect. This single cell is not enough to generate a lot of power. So, many cells are used together to form a panel. Additional layers of glass and adhesive act as protection for the solar cells. Solar cells are made of silicon. It is basically a semiconductor that is the cause of electricity generation. A solar cell is made up of two silicon layers. There is a positive charging layer called the p-type layer and the other is a negative charging layer called the n-type layer. The n-type layer can donate electrons and this layer resists light. The p-type layer can accept electrons and since they gain extra electrons, the area created for such electrons is call

What are transparent solar panels? Basically, conventional solar energy conversion uses common solar panels (solar photovoltaic panels). However, transparent solar panels use plain glass as the panel. And since glass is transparent, it is coated and made with special materials to allow the photovoltaic effect to pass through. This keeps the glass transparent and converts solar energy into electricity. So, you can imagine that every piece of glass, from window frames to automobile windows, can be used as solar panels. Therefore, no additional land space or roof is required to install solar panels. A building with this type of glass windows will generate electricity automatically. So, you can literally turn any sheet of glass or window into a photovoltaic cell. All light is made up of electromagnetic radiation spread across a spectrum of wavelengths, each containing energy that can potentially be extracted by a solar cell. However, the human eye can detect only a fraction of the waveleng

What is Polyvinyl Chloride? Polyvinyl chloride is known as PVC. And is flame retardant and self-extinguishing. and is used either as an insulation material or as a cladding material. PVC is an extremely versatile material that has traditionally been used extensively in the cable industry. PVC can be modified for both indoor and outdoor use, in both wet and dry conditions, conduit or direct burial, and high- and low-temperature applications. PVC also has resistance to various chemicals, including some oils and solvents. PVC is being replaced by low-smoke, halogen-free materials in certain applications, where fire conditions pose a greater risk to life and equipment.

Difference between permittivity and permeability Permeability Permeability is related to magnetic field. Permittivity The permittivity is related to the electric field. Permeability Permeability is a measure of the application or allowance for a magnetic field Permittivity Permittivity is a measure of resistance to an electric field. Permeability Permittivity is the electric displacement/intensity of the electric field. Permittivity Permeability is a measure of the magnetic induction/intensity of a magnetic field. Permeability Permeability is denoted by the Greek letter μ. Permittivity Permittivity is denoted by the Greek alphabet ϵ. Permeability The SI unit of permeability is henry/meter. Permittivity The SI unit of permittivity is farad/meter.

What is Permeability? Permeability is basically related to the magnetic field and is denoted by μ. and is measured by the magnitude of the magnetic induction or intensity of the magnetic field. It may vary depending on the type of material used, the strength of the magnetic field, the environmental characteristics of temperature and humidity etc.

What is permittivity? Basically permittivity is a property related to the electric field of the media. Suppose there is a medium between two conductors. Every medium contains atoms of electrons and neutrons. They are unbalanced or unbalanced which means placed anywhere in the media without any electrical interference. When an electric field is applied to a conductor, the atoms polarize themselves in the correct direction and this movement through them creates their own electric field, which opposes the external electric field applied to the conductor. And they start moving away from it. This opposition is known as permission. It measures the resistance offered against the formation of an electric field. If they are properly aligned and moving away from the electric field, it means that the medium has better permittivity. It is denoted by the Greek alphabet ϵ. This is represented as the electric displacement/intensity of the electric field. It may vary depending on the type of material

What is Pt 100?  Basically that A platinum resistance temperature detector (PRTD) has a resistance of 100Ω at 0°C with a temperature coefficient of 0.00385Ω/°C.

What is the application of bimetallic strips?  Bimetallic thermometers basically use bimetallic strips to measure local temperatures in process industries. And spiral bimetallic strips are used in air conditioning thermostats. And it is used for simple on/off switching applications.

What is thermal conductivity?  Thermal conduction is basically the flow or transfer of heat from a high-temperature region to a low-temperature region.

What is absolute zero?  Essentially, absolute zero is a temperature at which there is no molecular motion in the system. And at absolute zero, the energy of the molecule is zero.

What are the different temperature scales?   The basic temperature measurements are Fahrenheit (°F), Celsius or Centigrade (°C), Rankine (°R) and Kelvin (K).

What is heat?  Heat is basically a form of energy. When heat is applied to a body, the amplitude of vibration of its molecules increases. It increases body temperature. The rise in temperature is always proportional to the heat energy of the system. 

What is temperature?  Temperature is a measure of heat generated by the constant motion of molecular particles in a body. And temperature describes the relative hotness or coldness of a body by which it can give off or receive energy from other bodies.

What is an instrument?  Essentially, an instrument is a technology used to measure and control a process variable known as an instrument. And it is a device that is used to measure, monitor, display, etc. a process variable. The basic process variables in an instrument are pressure, flow, level and temperature. Pressure   Generally pressure is defined as force per unit area and mathematically known as pressure = F/A. And the unit of pressure is PSI, BAR, PASCAL, TORR, Kg/cm  Flow   Usually flow is defined as the rate of change of differential pressure. And the unit of flow is liter/minute, gallon/hour, kg/hour.  Level Level is basically the difference between two heights. And the level unit is mm, meter, centimeter, MMWC (millimeter water column).

What is Integrated Circuit?  Basically an integrated circuit is a small chip or micro chip and this chip contains diodes, resistors, capacitors and transistors. And these act as amplifiers, counters, oscillators, timers, computer memories or microprocessors. Two types of ICs are analog ICs and digital ICs.

What is HMI?  Basically HMI is known as human machine interface and it allows human to give direction as well as receive feedback from PLC. The HMI screen displays various types of indications and these indications are used to identify problems in process or instrument status such as on, off, feedback error and feedback error.  

Control Valve Interview Questions and Answers Q. What is a control valve? The control valve is the final component that directly changes the value of the manipulated variable by changing the rate of flow of the control agent. A control valve is a consists of an the operator and the valve body. The operator provides the power to change the position of the valve plug inside the body. The plug is connected to the operator by a stem, which slides through the stuffing box. An air signal from the controller is applied above the diaphragm. An increasing air signal from the controller is applied above the diaphragm. The rising air signal will push down the operator's stem against the force exerted by the spring on the diaphragm plate. The valve is adjusted so that the plug starts moving when 3 psi is applied to the diaphragm and touches the seat when 15 psi is applied to the diaphragm. As the air pressure increases, the valve will close. So the house "want to close". Another