Passive components Michael Pecht 1.1 Resistors University of maryland Resistor Characteristics.Resistor Types 1.2 Capacitors and Inductors Capacitors. Types of Capacitors. Inductors motorola 1.3 Transformers Glen ballou Types of Transformers. Principle of sformation. Electromagnetic Equation. Transformer Core· Transformer losses· Transformer C. Sankaran Connections Transformer Impedance 1.4 Electrical fuses atings. Fuse Performance. Selective Nick Angelopoulos Coordination· Standards· Products· Standard- Class h Gould Shawmut Company 1 Resistors Michael Pecht and Pradeep lall The resistor is an electrical device whose primary function is to introduce resistance to the flow of electric current. The magnitude of opposition to the flow of current is called the resistance of the resistor. A larger resistance value indicates a greater opposition to current flow The resistance is measured in ohms. An ohm is the resistance that arises when a current of one ampere is passed through a resistor subjected to one volt across its terminals. The various uses of resistors include setting biases, controlling gain, fixing time constants, matching and loading circuits, voltage division, and heat generation. The following sections discuss resistor characteristi and various resistor types. Resistor characteristics Voltage and Current Characteristics of Resistors The resistance of a resistor is directly proportional to the resistivity of the material and the length of the resistor and inversely proportional to the cross-sectional area perpendicular to the direction of current flow. The resistance R of a resistor is given by R A where p is the resistivity of the resistor material( Q2.cm), l is the length of the resistor along direction of current flow(cm), inherent property of materials. Good resistor materials typically have resistivities between 2 x 10- and 200x c 2000 by CRC Press LLC© 2000 by CRC Press LLC 1 Passive Components 1.1 Resistors Resistor Characteristics • Resistor Types 1.2 Capacitors and Inductors Capacitors • Types of Capacitors • Inductors 1.3 Transformers Types of Transformers • Principle of Transformation • Electromagnetic Equation • Transformer Core • Transformer Losses • Transformer Connections • Transformer Impedance 1.4 Electrical Fuses Ratings • Fuse Performance • Selective Coordination • Standards • Products • Standard— Class H • HRC • Trends 1.1 Resistors Michael Pecht and Pradeep Lall The resistor is an electrical device whose primary function is to introduce resistance to the flow of electric current. The magnitude of opposition to the flow of current is called the resistance of the resistor. A larger resistance value indicates a greater opposition to current flow. The resistance is measured in ohms. An ohm is the resistance that arises when a current of one ampere is passed through a resistor subjected to one volt across its terminals. The various uses of resistors include setting biases, controlling gain, fixing time constants, matching and loading circuits, voltage division, and heat generation. The following sections discuss resistor characteristics and various resistor types. Resistor Characteristics Voltage and Current Characteristics of Resistors The resistance of a resistor is directly proportional to the resistivity of the material and the length of the resistor and inversely proportional to the cross-sectional area perpendicular to the direction of current flow. The resistance R of a resistor is given by (1.1) where r is the resistivity of the resistor material (W · cm), l is the length of the resistor along direction of current flow (cm), and A is the cross-sectional area perpendicular to current flow (cm2 ) (Fig. 1.1). Resistivity is an inherent property of materials. Good resistor materials typically have resistivities between 2 ¥ 10–6 and 200 ¥ 10–6 W · cm. R l A = r Michael Pecht University of Maryland Pradeep Lall Motorola Glen Ballou Ballou Associates C. Sankaran Electro-Test Nick Angelopoulos Gould Shawmut Company