211 SRI RAMAKRISHNA MISSION VIDYALYA POLYTECHNIC COLLEGE.

   Human Machine Interface: A  Human-Machine Interface (HMI)  is a user interface that allows a human operator to interact with a machine or process.  HMI is typically used in industrial settings to allow operators to monitor and control processes, such as those in a factory or power plant. HMI can take a variety of forms, including graphical user interfaces (GUIs) on a computer, touchscreens, or physical control panels with buttons and displays. They are used to present process data to the operator, allow the operator to input commands and setpoints, and present alarms and other information. HMI is typically connected to a  programmable logic controller  (PLC), which is responsible for controlling the process based on input from the HMI and sensors in the field.  The HMI simply presents information to the operator and allows them to input commands, which are then sent to the PLC to be implemented.

 Alessandro Giuseppe Antonio Anastasio Volta (18 February 1745 – 5 March 1827) was an Italian physicist and chemist who was a pioneer of electricity and power[1][2][3] and is credited as the inventor of the electric battery and the discoverer of methane. He invented the voltaic pile in 1799, and reported the results of his experiments in 1800 in a two-part letter to the president of the Royal Society. With this invention Volta proved that electricity could be generated chemically and debunked the prevalent theory that electricity was generated solely by living beings. Volta's invention sparked a great amount of scientific excitement and led others to conduct similar experiments, which eventually led to the development of the field of electrochemistry.

  Transistor as an Amplifier Working   Very small current flows between a transistor's emitter and base when its base receives a small input signal. This low current then stimulates the flow of a much larger current between the emitter and collector, amplifying the input signal. The amount of bias current given to the base of a transistor controls how much amplification it can produce. Bias current is the flow of current across a transistor's base-emitter junction when there is no input signal. The quantity of bias current establishes the transistor's operating point and the maximum output signal that can be generated. Depending on the sort of circuit layout employed, the transistor can be utilized as a voltage amplifier or a current amplifier. In a typical emitter setup, the base receives the input signal while the collector receives the output signal. The transistor functions as a voltage amplifier in this design, amplifying the input signal voltage to a higher output sig...

 We use De Morgan’s theorems to solve the expressions of Boolean Algebra. It is a very powerful tool used in digital design. This theorem explains that the complements of the products of all the terms are equal to the sums of the complements of each and every term. Likewise, the complements of the sums of all the terms are equal to the products of the complements of each and every term. What are De Morgan’s Theorems? Two of the theorems were suggested by De Morgan that are extremely useful for Boolean Algebra. These two theorems have been discussed below in this article: Theorem 1 The LHS (left-hand side) of this theorem represents the NAND gate that has inputs A and B. On the other hand, the RHS (right-hand side) of this theorem represents the OR gate that has inverted inputs. The OR gate here is known as a Bubbled OR. Here is a table that shows the verification of the first theorem of De  Morgan:

  Speed Regulation of Induction Motors The speed regulation of induction motor is defined as the change in the motor speed with change in load. It is expressed as a fraction or percentage of full-load speed, i.e., S p e e d r e g u l a t i o n = N n l − N f l N f l × 100 % S p e e d r e g u l a t i o n = N n l − N f l N f l × 100 % Where, N n l N n l  is the no-load speed of the motor and  N f l N f l  is the full-load speed of the motor. The speed regulation of an induction motor is about 3% to 5%. Due to this small speed regulation, the induction motors are classified as the constant speed motors.

  Astable Multivibrators   are automatically triggered multivibrators. Multivibrators are non-sinusoidal oscillators capable of generating waveforms other than sine waves. Relaxation oscillators with regenerative switching circuits, such as the Astable Multivibrator, are the most widely used because they are easy to build and provide a constant square wave output. Due to their ability to oscillate independently without external inputs or assistance, Astable multivibrators are also known as free-running multivibrators. Astable Multivibrators, unlike Monostable Multivibrators or Bistable Multivibrators, are automatically triggered, so they toggle between their two unstable states, set and reset continuously, using a built-in trigger pulse. Circuit Diagram of Astable Multivibrator There are two switching transistors, a cross-coupled feedback network, and two time-delay capacitors in the stable circuit so that the state can change without external triggering. With this circuit, on...

  Advantages of Universal motor Simple and robust structure. Portable motor. It can be operated on ac and dc. High starting torque. It rotates at a very high speed (more than 3000 to 20000 rpm). This motor is easy to control. Disadvantages of Universal motor Very noisy motor. This motor has a shorter life span. The universal motor gets heated quickly during operation. Higher maintenance is required.

  An   electric bus   is a   bus   that is propelled using   electric motors   as opposed to an   internal combustion engine . Electric buses can store the needed   electricity   on board, or be fed continuously from an external source. The majority of buses storing electricity are   battery electric buses   (which this article mostly deals with), where the electric motor obtains energy from an   onboard battery pack , although examples of other storage modes do exist, such as the   gyrobus   which uses   flywheel energy storage . When electricity is not stored on board, it is supplied by contact with outside power sources. For example,   overhead wires   as in the   trolleybus , or with a   ground-level power supply , or through   inductive charging . Electric buses in  Bogotá , the city with the most electric buses outside of  China A  Massachusetts Bay Transportatio...