ACTIVE AND PASSIVE COMPONENTS.pdf

ACTIVE AND PASSIVE COMPONENTS In electrical and electronics engineering, the closed path followed by the electric current is known as electric circuit. Every electric circuit is composed of many circuit components such as sources of power, res...

ACTIVE AND PASSIVE COMPONENTS In electrical and electronics engineering, the closed path followed by the electric current is known as electric circuit. Every electric circuit is composed of many circuit components such as sources of power, resistors, capacitors, inductors, diode, etc. Therefore, the circuit components are the basic building blocks of an electrical or electronic circuit. Depending upon the power delivering or absorbing ability, the circuit components can be classified in following two types − Active components Passive components The most significant difference between active components and passive components is that an active component can supply power to an electric circuit, whereas a passive component cannot deliver power, it can only absorb the power in the circuit. What is an Active Component? In electronic components, Active components are electronic devices that need an external power source to operate actively. They mainly manipulate, amplify, switch, or control the flow of electric current or voltage in a circuit. Active components, like diodes, transistors, integrated circuits (ICs), and sensors require power to do their job. A circuit is an interconnection of components. These components are capable of performing active functions like amplification, rectification, and switching they are called active components. OR Active components are electronic devices that need an external power source to work. They actively control and manipulate the flow of electric current in a circuit. These components can amplify, switch, or generate electrical signals. OR An electric circuit element which can supply electric power to the circuit or power gain in the circuit, is known as an active element or active component. Some common examples of active circuit elements are energy sources (voltage sources or current sources), generators or alternators, semiconductor devices such as transistors, photodiodes, etc. The active elements are the circuit component which are entirely responsible for the flow of electric current in the circuit. Characteristics of Active Components Active Components require an external power supply to operate. Active Components produce energy in form of current or voltage. Active components can power gain in the electric circuit.  Active components can control the flow of current. Active components receive energy in the forms of thermal energy, chemical energy, hydraulic energy, and delivers in the circuit in the form of electrical energy. Working of Active Components An active component works as an alternating-current circuit in a device, which works to increase the active power, voltage or current. An active component is able to do this because it is powered by a source of electricity that is separate from the electrical signal. Working of Active components includes, Active components receive energy in the forms of thermal energy, chemical energy, hydraulic energy, and delivers in the circuit in the form of electrical energy. Therefore, a active components provide electric power or power amplification in an electric circuit. Some common examples of active circuit components are diodes, transistors, Integrated Circuits, etc. Types of Active Components Active components are mainly divided into three basic active electronic components which include: Diodes Transistors Integrated Circuits. Diodes Diode is a one-way valve for electricity. Diodes allow the current to pass through one way if it is forward biased (the anode with the positive terminal and the cathode with the negative one), and it prevents it from passing when it is reverse biased. Diodes consist of semiconductor materials, either silicon or germanium. It is a two terminal semiconductor device, these two terminals are called the anode and cathode. It lets the electricity to flow only in one direction.  Most diodes have painted line on one end showing the direction or flow. The negative side is normally white Current flow through diode only when positive voltage is applied to anode and negative voltage is connected to cathode If these voltages are reversed, then the current will not flow. Diode Applications of Diodes They act as shields for solar panels. They are used to protect loads from voltage spikes. They are used in voltage and converting it from AC to DC. They are used to allow an unidirectional flow of current in circuit. They differ by its power, and how much current it can handle. They act as an electronic check valve and convert alternating current into direct current (DC). Transistors Transistor is the most important invention of the last century, its invention led to the advancement of electronics in a large and amazing way. Transistors amplify and switch electronic signals. The transistor amplifies, connects and disconnects electrical signals (acts as an electronic switch). Transistors are able to amplify the power of a signal Bipolar Junction Transistors in which include NPN and PNP transistors are further classified based on their applications and characteristics:  NPN Transistor: The NPN transistor is commonly used for the amplification and switching in electronic circuits. It is named after the arrangement of its layers: N-type collector, P-type base, and N-type emitter. PNP Transistor: The PNP transistor is also used for the amplification and switching but with the opposite current flow compared to NPN. The terminals of the BJT bipolar transistor are: B: Base C: Collector E: Emitter Transistor Applications of Transistors They are used in amplifiers. They are used in digital logic circuits. They are used in voltage regulators. They are used in Logic Circuits  They are used in Temperature Control Systems It is used in converters. They are used in automatic switches Integrated Circuits (ICs) ICs integrate multiple electronic components into a single package, performing complex functions like microprocessors, memory storage, and specialized circuitry. An integrated circuit (IC) is a small semiconductor chip on which millions of electronic components such as resistors, capacitors and transistors are fabricated. The integrated circuit function is mainly to offer high- level functions and tasks like amplification, complex digital calculations i.e. microprocessors, and signal processing. The sole purpose of ICs is to increase the efficiency of the electronic devices, while reducing their size and manufacturing cost. An IC can function as an amplifier, oscillator, timer, counter, logic gate, microcontroller, or microprocessor. An integrated circuit (IC) can consist of thousands or even millions of: Transistors Resistors Capacitors Diodes  Integrated Circuits Applications of Integrated Circuits (ICs) IC’s are used to that combine multiple electronic components such as transistors, resistors, capacitors, into a single chip. IC’s are used to combines multiple electronic components. IC’s are used to reduce component size. IC’s are used to reduce power consumption. Other Active components include voltage sources like batteries ,current sources, generators, sensors and many other common components. These components are available as through-hole and components, and many are available in common packages with standard land patterns What is a Passive Component? The circuit element which can only absorb electrical energy and dissipates it in the form of heat or stores in either magnetic field or electric field is known as passive circuit component or simply passive component. Therefore, a passive component cannot provide electric power or power amplification in an electric circuit. Some common examples of passive circuit components are resistor, inductor, capacitor and transformer, etc. Difference between Active and Passive Components Both active and passive elements are the main parts of an electrical or electronic circuit. However, they are different from each other in many aspects. All the noticeable differences between active and passive circuit elements are enlisted in the following table. Basis of Active Component Passive Component Difference A circuit component A circuit element which which can deliver only absorbs the power power or power gain in and convert it in heat or Definition an electric circuit for stores infinite duration of time in electric field or magnetic is known as active field is known as passive component. component. The common examples of active components The examples of passive are energy sources components are resistor, Examples (voltage or current inductor, capacitor and source), generators, transformer, etc. semiconductor devices like transistors, solar cells, SCR, etc. Active components Role in the The passive components circuit behave as source of act as load in the circuit. power in the circuit.  Basis of Active Component Passive Component Difference Active components can Passive components cannot Power gain provide power gain in provide power gain. the electric circuit. Active components receive energy in the Passive components forms such as thermal receive electrical energy energy, chemical and either convert it in the Function energy, hydraulic other forms such as heat, energy, etc. and light, rotation, etc. or store delivers in the circuit in in the magnetic field or the form of electrical electric field. energy. Active components The passive components Control of cause current flow in current flow cannot control the current the circuit and control flow in the circuit. the flow of current. The slope of VI The slope of VI characteristics curve characteristics curve (i.e. Slope of VI (i.e. ratio of voltage to the ratio of voltage to graph the current) of an current) of a passive active element is component is positive at all negative. the points. For an active element, The VI curve of the passive Quadrant of graph the VI curve lies in the elements lies in the 1st and 2nd and 4th quadrant. 3rd quadrant. Active components can deliver as well as absorb the electrical A passive element can only Power power. For example, a absorb electrical power. It deliver or absorb battery, during is not capable for deliver charging absorbs power. electrical energy and during discharging  Basis of Active Component Passive Component Difference delivers electrical energy. Some active Passive components do not components require an require any external power external power source source to function. The to function. For passive components such Need of example, the active as resistor, inductor, external power source components like capacitor, etc. do not to function transistors and SCR require any source of use electrical energy to electricity to function, they function, i.e., to control use some other property to the power in the control the power in the circuit. circuit. Active components For passive components, Amplification have power gain more the power gain is less than than unity, so they can unity, hence they cannot amplify a signal. amplify a signal.