R R RR RR R R
Propaganda
2. Análise de Circuitos Elétricos Simples Redes e circuitos; Lei de Ohm; Fontes independentes e dependentes; Leis de Kirchhoff; Associação de resistores e fontes; Divisores de tensão e corrente. Ex.: Obter I. 8 mA Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Calcule a tensão que tem que ser aplicada ao ferro de solda, mostrado abaixo, para estabelecer uma corrente de 1,5 A, sendo a sua resistência interna de 80 Ω. E I .R (1,5 A) x(80 ) 120 V Gráfico da Lei de Ohm R V I Gráfico da Lei de Ohm Gráfico da Lei de Ohm Gráfico da Lei de Ohm Determine a resistência associada ao gráfico abaixo e compare com a Lei de Ohm. Para V = 6V e I = 3mA Rcc V I 6 3x10 3 2k Para o intervalo entre 6V e 8V R V I 2 1x10 3 2k Diodo Semicondutor Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Potência Elétrica 2 P V .I V R.I P P V R R.I 2 Para o exemplo do ferro de solda: P R.I 2 (80 ).(1,5 A) 180 W A curva característica I – V de uma lâmpada de filamento é mostrada a seguir. Se a tensão nominal de operação da lâmpada é 120 V, determine a potência dissipada e sua resistência. Solução: P V .I R V I (120).(0, 625) 120 0, 625 Obs.: I 75 W 192 P e V R P.R Potência Consumida Fornecida Eficiência Eficiência = Pi Po Pdissipada Po = Pi Wo (%) = x100% Wi Po (%) = x100% Pi Wo (%) = x100% Wi Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Wattímetros Um motor de 2 hp opera com eficiência de 75%. Qual a potência de entrada em watts? Se a tensão aplicada ao motor é 220 V, qual a corrente na entrada? Solução: (%) (2 hp).(746 W/ hp) Pi 0, 75 Pi Pi E.I Po x100% Pi 1.492 W 0, 75 I Pi E 1.989,33 W 1.989,33 220 9, 04 A total Robert L. Boylestad Introductory Circuit Analysis, 10ed. Po1 Po2 Po3 Pi1 Pi 2 Pi 3 1 2 3 Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Energia (W) P(W).t (s) Energia(kWh) = 1.000 Energia (W) P(W).t (s) Energia(kWh) = 1.000 Calcule a quantidade de energia (em kWh) necessária para manter uma lâmpada de filamento (60 W) acesa continuamente durante um ano. W P.t 1000 (60W).(24h/dia).(365dias) 1000 W 525.600(Wh) 1000 525, 6 kWh Medir de tensão - voltímetro Medir de tensão - voltímetro Medir corrente - amperímetro (a) Measuring the no-load voltage E; (b) measuring the short-circuit current. Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Segurança – categorias: Segurança – categorias: Multímetros digitais Amperímetros Fonte independente Fonte independente - práticas Ep E R.I L E Ep R.I L Toda fonte prática tem uma resistência interna, responsável pela dissipação (queda de tensão nominal). Fonte independente - práticas E Rs I s I Is RL I L IL Is Is RL I L Rs RL Rs Rs IL Conversão de fonte Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Conversão de fonte Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Conversão de fonte Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Associação de fontes Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Associação de fontes Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Ex.: Obter a corrente destacada na figura. Es I1 R1 Rs R1 Robert L. Boylestad Introductory Circuit Analysis, 10ed. 4.3 12 V 3 Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Es I1 R1 Rs R1 4.3 12 V 3 I2 Robert L. Boylestad Introductory Circuit Analysis, 10ed. E1 Rs E2 R2 17 5 3, 4 A Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Fontes de correntes de diferentes intensidades não podem ser ligadas em série. Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Fonte de corrente dependente Ex.: Transistor bipolar Classificação vc 2V id 1,5A Pd vd .id vd 2.vc 4V (4V).(1,5A) 6W Determinação do número de vezes que a Lei de Kirchhoff para correntes deve ser aplicada Ligação série Ligação paralelo Circuito série Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Determinar a resistência total e a corrente para cada circuito abaixo RT RT 20 110 Robert L. Boylestad Introductory Circuit Analysis, 10ed. I 60 20 I 35 110 3A 318, 2 mA RT 1, 63 M RT 10 k I 10 1, 63 M I 120 10k 6,135 A 12 mA Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Determinar a resistência desconhecida e a corrente I Robert L. Boylestad Introductory Circuit Analysis, 10ed. R RT 10 12 I 30 30 1A 8 Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Ilustrar o divisor de tensão V R1 R3 R2 R3 E R3 E RT Circuito paralelo Paralelo - Série Mesma tensão, corrente dividida Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Obter as correntes e a resistência equivalente I1 R2 R1 R2 IS R2 IS RT Ilustrar o divisor de corrente Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Obter as correntes, resistência e tensão Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Lei das correntes de Kirchhoff Lei das correntes de Kirchhoff Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Lei das correntes de Kirchhoff Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Lei das correntes de Kirchhoff Lei das correntes de Kirchhoff 4A 2A Robert L. Boylestad Introductory Circuit Analysis, 10ed. 2A Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Exemplo Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Exemplo Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Análise de malhas – complicado? Robert L. Boylestad Introductory Circuit Analysis, 10ed. Circuito em ponte Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Condição de equilíbrio para o circuito em ponte VR5 R1 R3 R2 R4 R1 R4 R2 R3 0 Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Pelo método de malhas: Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Ponte equilibrada R1 R3 Robert L. Boylestad Introductory Circuit Analysis, 10ed. R2 R4 R1 R4 R2 R3 Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Ponte equilibrada Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Transformação Y –Δ (T – π) Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Conceito Y –Δ Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Obtenção da resistência Ra-c Ra-c (Y) Ra-b R1 Ra-c ( ) R2 Ra-c R1 R3 RC ( RA RB ) e Rb-c RC RA RB RB ( RA RC ) RB RA RC R2 R3 RA ( RB RC ) RA RB RC Obtenção da resistência R3 R1 R2 RA RA RB RB RC RC RA RC RB RB RC RA RA RA RC RB RC RB R1 R2 R1 R3 R3 R2 R3 R1 R2 R1R3 R1 R2 R3 R1 R2 R1 R3 R2 R2 R3 Robert L. Boylestad Introductory Circuit Analysis, 10ed. Copyright ©2003 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Exemplo Observação: RA RB RC RY R 3 Exemplo Exemplo
