Analog Instruments Analog instruments are characterized by their continuous signals. A purely analog instrument measures, transmits, displays, and stores data in analog form. The signal processing is realized by analog components that are integrating together as functional blocks, as illustrated in Figure  Some examples of functional blocks are bridges, amplifiers, filters, oscillators, modulators, offset circuits, level converters, and buffers. Three basic components are common in all types of analog signal processing:- resistors, capacitors, and inductors. The main function of a resistor is to limit the current. The current will flow through a capacitor only if the voltage changes across it. In the case of inductors, voltage is established only as a result of a change in the current across it. Other analog components, including semiconductor devices such as diodes, transistors, operational amplifiers, and rectifiers, are based on these three basic elements. Two basic types of semic

  Step Up and Step Down Transformer Step up transformer A transformer that increases the voltage from primary to secondary (more secondary winding turns than primary winding turns) is called a step-up transformer. A step-up transformer is a type of transformer that converts the low voltage (LV) and high current from the primary side of the transformer to the high voltage (HV) and low current value on the secondary side of the transformer.  Step down transformer A Step Down Transformer is a device which converts high primary voltage to a low secondary voltage. In a Step Down Transformer, the primary winding of a coil has more turns than the secondary winding. A step-down transformer is a type of transformer that converts the high voltage (HV) and low current from the primary side of the transformer to the low voltage (LV) and high current value on the secondary side of the transformer.

  DP cell Impact  of Operating Environment   All of the sensors described in this module are widely used in control and instrumentation systems throughout the power station. Their existence will not normally be evident because the physical construction will be enclosed inside manufacturers packaging. However, each is highly accurate when used to measure the right quantity and within the rating of the device. The constraints are not limited to operating.pressure. Other factors include temperature, vapour content and vibration.  Vibration   The effect of vibration is obvious in the inconsistency of measurements, but the more dangerous result is the stress on the sensitive membranes, diaphragms and linkages that can cause the sensor to fail. Vibration can come from many sources. Some of the most common are the low level constant vibration of an unbalanced pump impeller and the larger effects of steam hammer. External vibration (loose support brackets and insecure mounting) can have the sa

 Screw Turbine The screw turbine is a water turbine which uses the principle of the Archimedean screw to convert the potential energy of water on an upstream level into work. Water flows into the turbine and its weight presses down onto the blades of the turbine, which in turn forces the turbine to turn.  Working of Screw Turbine The turbine consists of a rotor in the shape of an Archimedean screw which rotates in a semicircular trough. Water flows into the turbine and its weight presses down onto the blades of the turbine, which in turn forces the turbine to turn. Water flows freely off the end of the turbine into the river. The upper end of the screw is connected to a generator through a gearbox. The Archimedean screw turbine is applied on rivers with a relatively low head (from 0.1 m to 10 m) and on low flows (0.01 m³/s up to around 10 m³/s on one turbine). Due to the construction and slow movement of the blades of the turbine, the turbine is considered to be friendly to aquatic wil

  Light Emitting Diode A light releasing diode is an electric component that emits light when the electric current flows through it. It is a light source based on semiconductors. When current passes through the LED, the electrons recombine with holes emitting light in the process. It is a specific type of diode having similar characteristics as the p-n junction diode. This means that an LED allows the flow of current in its forward direction while it blocks the flow in the reverse direction. Light-emitting diodes are built using a weak layer of heavily doped semiconductor material. Based on the semiconductor material used and the amount of doping, an LED will emit a colored light at a particular spectral wavelength when forward biased. Working of Light Emitting Diode The holes lie in the valence band, while the free electrons are in the conduction band. When there is a forward bias in the p-n junction, the electron which is a part of the n-type semiconductor material would overrun the

  What is a DC motor? A DC motor is defined as a class of electrical motors that convert direct current electrical energy into mechanical energy. A DC motor is an electrical machine that converts electrical energy into mechanical energy. In a DC motor, the input electrical energy is the direct current which is transformed into the mechanical rotation. Types of DC motor Permanent Magnet DC Motor (PMDC Motor) Separately Excited DC Motor Self Excited DC Motor Shunt Wound DC Motor Series Wound DC Motor Compound Wound DC Motor Short shunt DC Motor Long shunt DC Motor Differential Compound DC Motor

  Tesla Turbine Tesla turbine is consists of a bladeless turbine that has an input through an air pipe nozzle. The body of the turbine has two outlets, one is for the incoming of the air and the other for the outgoing of the air. Apart from that, the rotating disc consists of 3 to 4 layers, which are joined together. There is a thin air gap between the layers where the air is passed at a very high speed. The rotating disc has two faces, outface and rear face. In both aspects, there is no scope for the air to flow outside the turbine body. The air can only enter through the inlet pipe and release through the outlet pipe. The turbine body consists of multiple disk rotor which is joined together. All the rotor discs are joined together on a common shaft where the disc can rotate. There is outer housing for the disks to be placed. The discs are usually connected through bolts. The front-end and rear-end have exhaust output ports through which the air can exit the turbine body. The placemen

  Single Phase and  three-phase transformer Single Phase transformer A single-phase transformer is a device that is capable of transferring electrical energy from one circuit to one or more circuits based on the concept of mutual induction. It comprises two coils – a primary and a secondary coil, which helps to transform the energy. The primary coil is connected to a single-phase supply, while the secondary is connected to a load. A single phase transformer is a type of transformer which operates on single-phase power. A transformer is a passive electrical device that transfers electrical energy from one circuit to another through the process of electromagnetic induction. It is most commonly used to increase (‘step up’) or decrease (‘step down’) voltage levels between circuits. A single phase transformer consists of a magnetic iron core serving as a magnetic transformer part and transformer cooper winding serving as an electrical part. A single phase transformer is a high-efficiency pi

  Transformers A transformer is a device used in the power transmission of electric energy. The transmission current is AC. It is commonly used to increase or decrease the supply voltage without a change in the frequency of AC between circuits. The transformer works on basic principles of electromagnetic induction and mutual induction. Introduction An electromagnetic device is used to transfer electric power from one circuit to another without change in frequency. Transformers are mainly used for stepping up and stepping down the voltages as desired by end users. Its working is based on the principle of mutual induction between two circuits linked by a common magnetic field. Transformers play a major part in the transmission and distribution of AC power. Parts of Basic Transformer A basic transformer consists of following two parts as shown in the figure below Parts of Transformer Winding Coils Core Winding Coils A transformer consists of two conducting winding coils which are separate

  Electromagnetic Induction When a conductor moves through a stationary magnetic field or a conductor is placed in a changing magnetic field, a voltage is developed across the conductor which in turns creates an electric current in the conductor. This process of creating current through changing magnetic field is called as electromagnetic induction and the current thus formed is called induced current. A figure showing the creation of electromagnetic induction when a wire is placed in a magnetic field is given below: Faraday's laws of Electromagnetic Induction These laws were formulated by an English physicist named Michael Faraday. Faraday's laws are the basic laws of electromagnetism. The working principle of most of electronic motors, transformers, generators and inductors etc is based on these laws. Faraday's First Law This law between gives the relationship induced current and electromotive force. This law states that when there is a change in the magnetic flux associa

  What is a Phase? A phase can be defined as the position of a point at a instant of time on a waveform cycle. Phase can also be expressed as the relative displacement between two or more waves having similar frequency. A complete cycle of a waveform is 360° of phase as shown in figure below A wave of certain frequency that is occurred before or ahead of another wave of same frequency is called a leading phase. A wave that is occurred after or behind another wave of same frequency is called a lagging phase.

  Stepper Motor A stepper motor, also known as step motor or stepping motor, is a brushless DC electric motor that divides a full rotation into a number of equal steps. The motor's position can be commanded to move and hold at one of these steps without any position sensor for feedback (an open-loop controller), as long as the motor is correctly sized to the application in respect to torque and speed. Stepper Motor Working Principle Stepper motors are DC motors that move in discrete steps. They have multiple coils that are organized in groups called “phases”. By energizing each phase in sequence, the motor will rotate, one step at a time. With a computer controlled stepping you can achieve very precise positioning and/or speed control. For this reason, stepper motors are the motor of choice for many precision motion control applications. Stepper Motor Operation Stepper motors work in very specific way, a standard stepper motor will have two or more coils that charge and discharge w

  Inductors Inductor is  also called a coil, choke, or reactor, is a passive two-terminal electrical component that stores energy in a magnetic field when electric current flows through it. Inductors much like conductors and resistors are simple components that are used in electronic devices to carry out specific functions. Normally, inductors are coil-like structures that are found in electronic circuits. The coil is an insulated wire that is looped around the central core. Inductors are mostly used to decrease or control the electric spikes by storing energy temporarily in an electromagnetic field and then releasing it back into the circuit. What is Inductor? An inductor is a passive component that is used in most power electronic circuits to store energy in the form of magnetic energy when electricity is applied to it. One of the key properties of an inductor is that it impedes or opposes any change in the amount of current flowing through it. Whenever the current across inductor ch

  Capacitor A capacitor is a passive two-terminal electrical component used to store energy electrostatically in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical conductors (plates) separated by a dielectric (i.e., insulator). The conductors can be thin films of metal, aluminum foil or disks, etc. The 'nonconducting' dielectric acts to increase the capacitor's charge capacity. A dielectric can be glass, ceramic, plastic film, air, paper, mica, etc. Capacitors are widely used as parts of electrical circuits in many common electrical devices. Unlike a resistor, a capacitor does not dissipate energy. Instead, a capacitor stores energy in the form of an electrostatic field between its plates. When there is a potential difference across the conductors (e.g., when a capacitor is attached across a battery), an electric field develops across the dielectric, causing positive charge (+Q) to collect on one plate and negative cha

  Resistor A passive electrical component with two terminals that are used for either limiting or regulating the flow of electric current in electrical circuits. The main purpose of resistor is to reduce the current flow and to lower the voltage in any particular portion of the circuit. It is made of copper wires which is coiled around a ceramic rod and the outer part of the resistor is coated with an insulating paint. SI Unit of Resistor is Ohm. What is a resistor? A resistor is a passive two-terminal electrical component that limits the current flowing in electrical or electronic circuits. Its property to resist the flow of current is called resistance, expressed in ohm (Ω), named after German physicist Georg Simon Ohm. Resistors are available in different sizes. Its size is directly proportional to its power rating. The power rating is the maximum amount of power that a resistor can dissipate without being damaged by excessive heat build-up. The larger the surface area covered by a

Control Valve question and answers 1. What is control valve? A power operated device used to modify the fluid flow rate in a process control system. It usually consists of a body or valve and an actuator, which responds to a signal from the controlling system and changes the position of a flow controlling element in the valve. 2. Can two control valves be used in series in high pressure drop applications?  Dropping the pressure across two valves rather than one is theoretically better. However, in practice, the two valves will not usually control well together unless the process can operate with a very low proportional band with slow response times. A better and usually less expensive approach is to use a valve that is designed with multiple pressure drop restrictions inside the trim. 3. What is the valve seat? The valve seat is that the apron for an outlined flow through opening within the valve through that the medium to be regulated needs to flow. 4. What is the valve cone? The valv