 Hello, I am Milka Jagle working as assistant professor in Walchent Institute of Technology Department of Mechanical Engineering, Sulapur. Today, we are going to see introduction to systems. What are various types of systems? So let us see learning outcome. At the end of this session, students will be able to describe various types of systems. So these are the contents, mechanical system, electronic system, computer control system, pneumatic systems, subsystems, open loop and closed loop control systems. So firstly, let us see the mechanical systems. Before we go for mechanical systems, so I just want you to take to the scenario of why we need systems. All our machines and tools can work properly if they have a proper control. It will be difficult for us to control the machines, tools and their applications if they don't have a control on them. That's why we need some systems to get the work done in time and with accuracy. We need control systems to regulate, direct or command the system or the other systems. A system usually contains main parts such as input, process and output. So let us see the mechanical system. A mechanical system is a device made up of various mechanical parts. The input which is provided to the mechanical system is the effort. In mechanical system, the effort is provided as an input. When the effort is applied, then it gives certain motion which moves a load. The various examples of mechanical systems are gears and levers. So the figure one shows the examples of mechanical system. The figure A shows the can opener. In this, the effort is required to do the operation that is opening the cap of a can. And the figure B shows the corkscrew. In this, the effort is applied to open the cork. So let us see what is electronic system. Electronic system is a system that employs electronic signals to control the devices. Electronic devices like radios, telephones, mobiles and computers. The input of electronic signals are processed and they generate the control signals which can operate the various devices like LCDs and amplifiers. Electronic systems can carry out many operations like monitoring, measuring, transmitting the information, calculating and etc. Electronic systems include semiconducting diodes, capacitors which are mounted on the electronic circuits. You see the figure C shows the circuit on which resistors and diodes and are used. So figure number two A shows the mobile phone which is electronic system. Figure B shows portable computer and the figure C shows electronic circuit board. Now let us see computer control system. Computer control systems uses a computer to control its output devices according to input signals. It works same as that of electronic systems. Computer control system works on preset program. Computer based system does the high speed calculations in very less duration of time and it gives the output on the basis of preset programs. Let us see the example of computer based system that is CNC press break here. The preset programs are used to get the desired output and we can also see the figure B shows all the computer controlled home appliances such as laptops, printers, mobile phones etc. Pneumatic systems. Pneumatic system is a system that uses compressed air to transport and control the energy. Air is pressurized into the cylinder to generate the energy and these pressurized air is passed through the seal pipes to the input where the pressurized air is used to generate the force by which we can get the output. So let us see the examples of pneumatic systems. First is ship pneumatic system and the second is pipe welding clamp. So now I want you to pause the video for few seconds and think about why do you need a control system. So what is the use of control system? As we have said like control system is used to regulate, direct or command the system. So let us see the first factor is safety. The plant or process must be safe to operate. The more complex or dangerous the plant or process, the greater is the need for automatic controls and safeguard the protocol. Stability. The plant or process should work steadily, predictably and repeatedly without fluctuations or unplanned shutdowns. Third is accuracy. This is a primary requirement in factories and buildings to prevent spoilage, increase quality and production rates and to maintain the comfort. These are the fundamental economic efficiency. So these are the main factors which states the need of control system. Now let us see what are subsystems. A subsystem may comprise some relatively small parts, they are known as subsystems. So before going to subsystems, let us see what is a system? I will give an example of a bulb. A switch is used to light a bulb is known as a simple system. A switch is used to on or off the bulb is known as a system. So these are figure A shows sight seeing lift and figure B shows lift in a hospital. So before going to the subsystem, every subsystem is divided into various simple systems. So let us take an example of lift. For proper operation of a lift, many factors and many, there should be a cooperation of many activities such as door opening mechanism, lightning mechanisms, door many mechanisms like door opening system, lightning system, ventilation system, safety system. These all systems need to work in cooperative with each other, then a lift can work successfully that is taking the passengers for different storage with safety. So you can also see a lift in a hospital which is used to carry the patients for different storage. As I said, a lift system is divided into many subsystems like driving, lightning, door opening, security system, control system, ventilation system and safety system. So the next type of system is open look control system. A control system in which the control action is totally independent of the output. Then the system is known as open look control system. So the figure number 7 shows a block diagram for open look control system. Here the input is given to the controller where the actuating or controlling signal is given to the plant and it gives the output. There is no any relation between input and output. So it is known as an open look control system. So let's see what is closed look control system. The main difference between open loop and closed loop system is the feedback element which is present in the closed loop control system. So a closed loop control system, it's a system in which output has an effect on the input so as the input quantity will adjust itself based on the output generated. The figure number 8 shows closed loop control system in which the feedback is taken from the output and it is given to the controller so as to generate the required output. These are the references.