Pengantar Teknik Elektro Elektronika II

Standar Kompetensi Mahasiswa mampu menghitung persamaan dasar dan memahami profesi yang bisa ditekuni bidang elektronika

Rujukan Valery Vodovozov, Introduction to Electronic Engineering, 2010 Alfred D. Chandler, Jr., Inventing the Electronic Century, 2005

Electric circuit An electric circuit is an interconnection of electrical elements linked together in a closed path so that electric current may flow continuously Circuit diagrams are the standard for electrical engineers

Rate of flow of charge form node a to node b Rate of flow of charge form node b to node a (i = current) A direct current (dc) is a current of constant magnitude An alternating current (ac) is a current of varying magnitude and direction

Voltage Driving “force” of electrical current between two points V ab V ba Voltage at terminal a with respect to terminal b Voltage at terminal b with respect to terminal a V ab = -V ba Note: In a circuit, voltage is often defined relative to “ground”

Voltage The voltage across an element is the work (energy) required to move a unit of positive charge from the “ - ” terminal to the “ + ” terminal A volt is the potential difference (voltage) between two points when 1 joule of energy is used to move 1 coulomb of charge from one point to the other

Power The rate at which energy is converted or work is performed A watt results when 1 joule of energy is converted or used in 1 second

Circuit schematic example

Circuit elements

Resistors Resistivity (ρ) is the ability of a material to resist current flow. The units of resistivity are Ohm-meters (Ω-m) Resistance (R) is the physical property of an element that impedes the flow of current. The units of resistance are Ohms (Ω) 1.68×10 −8 Ω·m Example: Resistivity of copper Resistivity of glass to Ω·m

Resistors

Resistor Labels Wire-wound resistors have a label indicating resistance and power ratings. A majority of resistors have color bars to indicate their resistance magnitude. There are usually 4 to 6 bands of color on a resistor. As shown in the figure below, the right most color bar indicates the resistor reliability, however, some resistor use this bar to indicate the tolerance. The color bar immediately left to the tolerance bar (C), indicates the multipliers (in tens). To the left of the multiplier bar are the digits, starting from the last digit to the first digit. Resistor value =

Resistors

Metric Units and Conversions Abbreviation Means Multiply unit by Or p pico n nano µ micro m milli Unit k kilo 1, M mega 1,000, G giga 1,000,000,

Digital Multimeter 1 DMM is a measuring instrument An ammeter measures current A voltmeter measures the potential difference (voltage) between two points An ohmmeter measures resistance A multimeter combines these functions, and possibly some additional ones as well, into a single instrument

Digital Multimeter 2 Voltmeter Parallel connection Ammeter Series connection Ohmmeter Without any power supplied Adjust range (start from highest limit if you don ’ t know)

Ammeter Connection Break the circuit so that the ammeter can be connected in series All the current flowing in the circuit must pass through the ammeter An ammeter must have a very LOW input impedance

Voltmeter Connection The voltmeter is connected in parallel between two points of circuit A voltmeter should have a very HIGH input impedance

Ohmmeter Connection An ohmmeter does not function with a circuit connected to a power supply Must take it out of the circuit altogether and test it separately

Resistors in Series R total =R 1 +R 2 R total =1+1=2kΩ

Resistors in Parallel

Exercise 1

Ohm’s Law (remember, R is in Ω and ρ is in Ω-m)

Capacitors

A capacitor consists of a pair of conductors separated by a dielectric (insulator). (ε indicates how penetrable a subtance is to an electric field) Electric charge is stored in the plates – a capacitor can become “charged” When a voltage exists across the conductors, it provides the energy to move the charge from the positive plate to the other plate.

Capacitors Capacitance (C) is the ability of a material to store charge in the form of separated charge or an electric field. It is the ratio of charge stored to voltage difference between two plates. Capacitance is measured in Farads (F)

Capacitors The capacitor plate attached to the negative terminal accepts electrons from the battery. The capacitor plate attached to the positive terminal accepts protons from the battery. What happens when the light bulb is initially connected in the circuit? What happens if you replace the battery with a piece of wire?

Energy storage Work must be done by an external influence (e.g. a battery) to separate charge between the plates in a capacitor. The charge is stored in the capacitor until the external influence is removed and the separated charge is given a path to travel and dissipate. Work exerted to charge a capacitor is given by the equation:

Capacitor Variations Ceramic capacitors –very popular nonpolarized capacitor –small, inexpensive, but poor temperature stability and poor accuracy –ceramic dielectric and a phenolic coating –often used for bypass and coupling applications Electrolytic –Aluminum, tantalum electrolytic –Tantalum electrolytic capacitor has a larger capacitance when compared to aluminum electrolytic capacitor –Mostly polarized. –Greater capacitance but poor tolerance when compared to nonelectrolytic capacitors. –Bad temperature stability, high leakage, short lives Axial leadRadial lead

Capacitor Variations Mylar –very popular, nonpolarized –reliable, inexpensive, low leakage –poor temperature stability Mica –extremely accurate, low leakage current –constructed with alternate layers of metal foil and mica insulation, stacked and encapsulated –small capacitance –often used in high-frequency circuits (i.e. RF circuits)

Capacitor Reading Example —I Thus, we have a 0.1  F capacitor with ±10% tolerance.

Capacitor Reading Example —II

Inductors An inductor is a two terminal element consisting of a winding of N turns capable of storing energy in the form of a magnetic field Inductance (L) is a measure of the ability of a device to store energy in the form of a magnetic field. It is measured in Henries (H)

Inductors μ 0 = permeability of free space = 4π × 10 −7 H/m K = Nagaoka coefficient N = number of turns A = area of cross-section of the coil in m 2 l = length of coil in m Inductance in a cylindrical coil

Inductors The magnetic field from an inductor can generate an induced voltage, which can be used to drive current While building the magnetic field, the inductor resists current flow

Inductors What happens to the light bulb when the switch is closed? What happens to the light bulb when the switch is then opened?

Series circuit example

Parallel Circuit example

Rangkaian Paralel

Rangkaian Seri

Profesi bidang Elektronika RnD : Polytron, pabrik pcb, Technical Support : peralatan instrumentasi Perancang IC