{"id":2184,"date":"2026-10-15T01:16:34","date_gmt":"2026-10-15T00:16:34","guid":{"rendered":"https:\/\/wpcalc.com\/pt\/engenharia\/constante-de-tempo-rc\/"},"modified":"2026-10-15T01:16:34","modified_gmt":"2026-10-15T00:16:34","slug":"constante-de-tempo-rc","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/pt\/engenharia\/constante-de-tempo-rc\/","title":{"rendered":"Constante de tempo RC"},"content":{"rendered":"<section class=\"not-prose calculator-box\" aria-labelledby=\"calculator-title\"><div class=\"flex items-baseline sm:items-center justify-between gap-2 sm:gap-3\"><div class=\"flex flex-col sm:flex-row sm:items-center gap-2\"><span class=\"icon icon-calculator text-primary-700! text-base! dark:text-primary-300!\" aria-hidden=\"true\"><\/span><h2 id=\"calculator-title\" class=\"text-lg font-display font-bold\">Descubra a velocidade de carga e descarga do seu circuito RC<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"2184\" data-favorite-title=\"Constante de tempo RC\" data-favorite-url=\"https:\/\/wpcalc.com\/pt\/engenharia\/constante-de-tempo-rc\/\" data-favorite-excerpt=\"Informe qualquer valor de resist\u00eancia e capacit\u00e2ncia e obtenha instantaneamente a constante de tempo RC (\u03c4), al\u00e9m dos tempos de carga e descarga para 50%, 90%, 95% e 99% da tens\u00e3o final.\" aria-label=\"Adicionar aos favoritos\" data-favorite-icon=\"icon icon-electrical\">\n    <span class=\"icon icon-shape-star-empty\" aria-hidden=\"true\"><\/span>\n  <\/button>\n  <div class=\"calcdash-favorite__tip\" aria-hidden=\"true\">\n   <span class=\"favorite-tooltip\" id=\"favorite-tooltip\"><\/span>\n  <\/div>\n  <span class=\"sr-only\" role=\"status\" id=\"favorite-status\"><\/span>\n<\/div><\/div><form action=\"https:\/\/wpcalc.com\/pt\/engenharia\/constante-de-tempo-rc\/\" method=\"POST\" class=\"calculator\" id=\"calculator-2184\" data-post=\"2184\"><fieldset class=\"fieldset-input is-2\"><legend class=\"sr-only\">Campos de entrada<\/legend><div class=\"field has-term\" id=\"input-1\"><label for=\"field-1\">Resist\u00eancia (R)<\/label><div class=\"term\">R<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"text\" name=\"resistncia_r\" id=\"field-1\" aria-describedby=\"calc-info-1\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0.001\" value=\"10\"\/><div class=\"grid grid-cols-1\"><select id=\"field-2\" name=\"unidade_de_resistncia\" aria-label=\"Unidade de resist\u00eancia\"><option value=\"ohm\">\u03a9<\/option><option value=\"kohm\" selected>k\u03a9<\/option><option value=\"Mohm\">M\u03a9<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><small id=\"calc-info-1\">Valor do resistor na rede RC<\/small><\/div><div class=\"field has-term\" id=\"input-2\"><label for=\"field-3\">Capacit\u00e2ncia (C)<\/label><div class=\"term\">C<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"text\" name=\"capacitncia_c\" id=\"field-3\" aria-describedby=\"calc-info-3\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0.001\" value=\"100\"\/><div class=\"grid grid-cols-1\"><select id=\"field-4\" name=\"unidade_de_capacitncia\" aria-label=\"Unidade de capacit\u00e2ncia\"><option value=\"pF\">pF<\/option><option value=\"nF\">nF<\/option><option value=\"uF\" selected>\u00b5F<\/option><option value=\"mF\">mF<\/option><option value=\"F\">F<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><small id=\"calc-info-3\">Valor do capacitor na rede RC<\/small><\/div><div class=\"field is-single\" id=\"input-3\"><label for=\"field-5\">Modo do circuito<\/label><div class=\"grid grid-cols-1\"><select id=\"field-5\" name=\"modo_do_circuito\"><option value=\"charge\" selected>Carga (a tens\u00e3o sobe)<\/option><option value=\"discharge\">Descarga (a tens\u00e3o cai)<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><\/fieldset><div class=\"buttons\"><button type=\"submit\" data-text=\"Recalcular\" id=\"calculate-button\" data-post=\"2184\">Calcular<\/button><button type=\"reset\">Redefinir<\/button><\/div><div class=\"field is-checkbox hidden!\" id=\"field-auto-calc\"><input type=\"checkbox\" id=\"auto-calc\"><label for=\"auto-calc\">Calcular automaticamente<\/label><small>Se ativado, o resultado \u00e9 atualizado automaticamente quando voc\u00ea altera qualquer valor.<\/small><\/div><div class=\"fieldset-result is-hidden\" aria-labelledby=\"result-title\" aria-live=\"polite\" role=\"region\"> <h3 class=\"result-title bg-gradient-to-r from-primary-50 to-gray-50 dark:from-primary-900 dark:to-gray-800\" id=\"result-title\"><span class=\"icon icon-s-pulse\" aria-hidden=\"true\"><\/span> Resultados de temporiza\u00e7\u00e3o do circuito RC<\/h3><div class=\"result-box\"><div class=\"field-result\" id=\"output-1\"><span class=\"field-title\"><span>Constante de tempo<\/span><span class=\"result-term\">\u03c4<\/span><\/span><span class=\"field-value\" id=\"result-1\" data-unit=\"s\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copiar resultado\" aria-label=\"Copiar resultado\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result is-column\" id=\"output-2\"><span class=\"field-title\"><span>Constante de tempo (formato leg\u00edvel)<\/span><\/span><span class=\"field-value\" id=\"result-2\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copiar resultado\" aria-label=\"Copiar resultado\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result\" id=\"output-3\"><span class=\"field-title\"><span>Tempo para atingir 50%<\/span><span class=\"result-term\">t\u2085\u2080<\/span><\/span><span class=\"field-value\" id=\"result-3\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copiar resultado\" aria-label=\"Copiar resultado\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result\" id=\"output-4\"><span class=\"field-title\"><span>Tempo para atingir 90%<\/span><span class=\"result-term\">t\u2089\u2080<\/span><\/span><span class=\"field-value\" id=\"result-4\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copiar resultado\" aria-label=\"Copiar resultado\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result\" id=\"output-5\"><span class=\"field-title\"><span>Tempo para atingir 95%<\/span><span class=\"result-term\">t\u2089\u2085<\/span><\/span><span class=\"field-value\" id=\"result-5\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copiar resultado\" aria-label=\"Copiar resultado\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result\" id=\"output-6\"><span class=\"field-title\"><span>Tempo para atingir 99%<\/span><span class=\"result-term\">t\u2089\u2089<\/span><\/span><span class=\"field-value\" id=\"result-6\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copiar resultado\" aria-label=\"Copiar resultado\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result is-column\" id=\"output-7\"><span class=\"field-title\"><span>Tabela de marcos (1\u03c4 \u2013 5\u03c4)<\/span><\/span><span class=\"field-value\" id=\"result-7\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copiar resultado\" aria-label=\"Copiar resultado\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><\/div><div class=\"result-actions\"><button type=\"button\" class=\"copy-link\"><svg viewBox=\"0 0 20 20\" fill=\"currentColor\" aria-hidden=\"true\"><path d=\"M12.232 4.232a2.5 2.5 0 0 1 3.536 3.536l-1.225 1.224a.75.75 0 0 0 1.061 1.06l1.224-1.224a4 4 0 0 0-5.656-5.656l-3 3a4 4 0 0 0 .225 5.865.75.75 0 0 0 .977-1.138 2.5 2.5 0 0 1-.142-3.667l3-3Z\"\/><path d=\"M11.603 7.963a.75.75 0 0 0-.977 1.138 2.5 2.5 0 0 1 .142 3.667l-3 3a2.5 2.5 0 0 1-3.536-3.536l1.225-1.224a.75.75 0 0 0-1.061-1.06l-1.224 1.224a4 4 0 1 0 5.656 5.656l3-3a4 4 0 0 0-.225-5.865Z\"\/><\/svg><span class=\"copy-link__text\">Copiar link para este c\u00e1lculo<\/span><\/button><span class=\"sr-only\" role=\"status\" id=\"copy-link-status\"><\/span><\/div><\/div><a href=\"#respond\" class=\"hidden transition-opacity duration-300 opacity-0 w-50 text-sm justify-center items-center gap-2 px-4 py-2 rounded bg-gray-200 text-gray-700 hover:bg-gray-300\" id=\"leave-comment\"><span class=\"icon icon-comments\" aria-hidden=\"true\"><\/span>Deixar um coment\u00e1rio<\/a><\/form><\/section><section id=\"calc-reactions\" class=\"not-prose hidden my-12 bg-gradient-to-r from-primary-50 to-gray-50 border border-indigo-100 rounded-xl px-6 py-4 shadow-sm\" data-post=\"2184\" aria-live=\"polite\" aria-labelledby=\"calc-reactions-title\"><p id=\"calc-reactions-title\" class=\"text-sm text-gray-500 text-center mb-2\">O que voc\u00ea achou deste resultado?<\/p><div role=\"group\" aria-labelledby=\"calc-reactions-title\" class=\"grid grid-cols-3 sm:flex sm:flex-row sm:justify-around gap-4 sm:items-center sm:flex-wrap\"><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"like\"><span class=\"reaction-count\" data-reaction-count=\"like\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude00 <\/span><span class=\"reaction-description font-medium\">Curti <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"helpful\"><span class=\"reaction-count\" data-reaction-count=\"helpful\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\udca1 <\/span><span class=\"reaction-description font-medium\">\u00datil <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"confused\"><span class=\"reaction-count\" data-reaction-count=\"confused\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude15 <\/span><span class=\"reaction-description font-medium\">Confuso <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"disappointed\"><span class=\"reaction-count\" data-reaction-count=\"disappointed\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude1e <\/span><span class=\"reaction-description font-medium\">Decepcionado <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"inaccurate\"><span class=\"reaction-count\" data-reaction-count=\"inaccurate\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\u274c <\/span><span class=\"reaction-description font-medium\">Impreciso <\/span><\/button><\/div><div id=\"reaction-message\" class=\"hidden mt-8 rounded-md border border-primary-100 bg-white\/50 backdrop-blur-sm px-4 py-2 text-sm text-center shadow-sm\"><\/div><\/section><div class=\"calcdash-ad not-prose calcdash-ad--calc_result calcdash-ad--in-article\"><ins class=\"adsbygoogle\" style=\"display:block\" data-ad-client=\"ca-pub-1721569815777345\" data-ad-slot=\"6317458308\" data-ad-layout=\"in-article\" data-ad-format=\"fluid\"><\/ins><script>(adsbygoogle = window.adsbygoogle || []).push({});<\/script><\/div>\n<style id=\"wpcoderpro-inline-1\">.formula-box {\r\n\tborder-bottom: none !important;\r\n}<\/style><section class=\"formula-box\" aria-labelledby=\"formula-title\">\r\n\t<div id=\"formula-title\" class=\"not-prose font-display mb-4\"><span class=\"icon icon-formula\" aria-hidden=\"true\"><\/span><h2>F\u00f3rmula da constante de tempo RC<\/h2><\/div>\r\n\t<figure class=\"not-prose formula\">\r\n\t\t<figcaption class=\"formula-title\">F\u00f3rmula<\/figcaption>\r\n\t\t<div class=\"text-base text-gray-800\" id=\"formula\">\n\\[ \\tau = R \\times C \\]\n\\[ t_f = -\\tau \\, \\ln(1 - f) \\quad \\text{(tempo para atingir a fra\u00e7\u00e3o } f \\text{ durante a carga)} \\]\n\\[ V(t) = V_0 \\left(1 - e^{-t\/\\tau}\\right) \\quad \\text{(carga)}, \\qquad V(t) = V_0 \\, e^{-t\/\\tau} \\quad \\text{(descarga)} \\]\n<\/div>\r\n\t<\/figure>\r\n\t<\/p>\n<p><strong>Onde:<\/strong><\/p>\n<ul>\n<li>\\(\\tau\\) \u2014 constante de tempo, em segundos (s)<\/li>\n<li>\\(R\\) \u2014 resist\u00eancia, em ohms (\u03a9)<\/li>\n<li>\\(C\\) \u2014 capacit\u00e2ncia, em farads (F)<\/li>\n<li>\\(V_0\\) \u2014 tens\u00e3o de alimenta\u00e7\u00e3o (carga) ou tens\u00e3o inicial do capacitor (descarga)<\/li>\n<li>\\(f\\) \u2014 fra\u00e7\u00e3o desejada da tens\u00e3o final, por exemplo 0,9 para 90%<\/li>\n<\/ul>\n<p>A primeira equa\u00e7\u00e3o define a constante de tempo: o produto da resist\u00eancia pela capacit\u00e2ncia. A segunda converte qualquer n\u00edvel-alvo, como 90% de carga, em um tempo decorrido. J\u00e1 as equa\u00e7\u00f5es exponenciais descrevem a tens\u00e3o completa sobre o capacitor durante a carga ou a descarga.<\/p>\n<p>\r\n<\/section>\n<style id=\"wpcoderpro-inline-2\">.calculation-box {\r\n\tborder-bottom: none !important;\r\n}<\/style><section id=\"calculation\" class=\"calculation-box\" aria-labelledby=\"calculation-title\">\r\n\t<div id=\"calculation-title\" class=\"not-prose font-display\"><span class=\"icon icon-unordered-list\" aria-hidden=\"true\"><\/span><h2>Constante de tempo RC \u2013 Exemplo de c\u00e1lculo<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Exemplo:<\/strong> um capacitor de 100 \u00b5F carrega atrav\u00e9s de um resistor de 10 k\u03a9 a partir de uma alimenta\u00e7\u00e3o de 12 V. Quanto tempo at\u00e9 ele atingir 90% da carga?<\/p>\n<p>\\[ \\tau = R \\times C = 10{,}000 \\ \\Omega \\times 100 \\times 10^{-6}\\ \\text{F} = 1\\ \\text{s} \\]<\/p>\n<p>\\[ t_{90} = -\\tau \\ln(1 - 0.9) = -1 \\times \\ln(0.1) \\approx 2.303\\ \\text{s} \\]<\/p>\n<p><strong>Resultado:<\/strong> a constante de tempo \u00e9 de 1 s, e o capacitor atinge 90% de 12 V (10,8 V) ap\u00f3s cerca de 2,3 s.<\/p>\n<p>\n\r\n<\/section>\n<h2>Como usar a calculadora<\/h2>\n<ol>\n<li>Digite o valor da <strong>Resist\u00eancia (R)<\/strong> e escolha sua unidade: \u03a9, k\u03a9 ou M\u03a9.<\/li>\n<li>Digite o valor da <strong>Capacit\u00e2ncia (C)<\/strong> e escolha sua unidade: pF, nF, \u00b5F, mF ou F.<\/li>\n<li>Escolha o <strong>Modo do circuito<\/strong>: \"Carga (a tens\u00e3o sobe)\" ou \"Descarga (a tens\u00e3o desce)\". Isso muda apenas a reda\u00e7\u00e3o da tabela de marcos; a constante de tempo em si \u00e9 a mesma.<\/li>\n<li>Leia os resultados: a constante de tempo em segundos e em forma leg\u00edvel (ms, \u00b5s, ns), os tempos para atingir 50%, 90%, 95% e 99% da tens\u00e3o final e uma tabela de marcos cobrindo de 1\u03c4 a 5\u03c4.<\/li>\n<\/ol>\n<h2>O que significa a constante de tempo RC<\/h2>\n<p>Quando um capacitor carrega atrav\u00e9s de um resistor, sua tens\u00e3o n\u00e3o salta direto para o valor da alimenta\u00e7\u00e3o \u2014 ela sobe ao longo de uma curva exponencial. A constante de tempo RC, \\(\\tau\\) (tau), \u00e9 a escala de tempo caracter\u00edstica dessa curva: ap\u00f3s uma constante de tempo, um capacitor em carga atinge 63,2% da tens\u00e3o de alimenta\u00e7\u00e3o, e um capacitor em descarga cai para 36,8% da tens\u00e3o inicial. Depois de cerca de 5\u03c4, o circuito \u00e9 considerado totalmente carregado ou descarregado (mais de 99% do caminho percorrido), pois a diferen\u00e7a restante \u00e9 pequena demais para importar na maioria das aplica\u00e7\u00f5es.<\/p>\n<p>A constante de tempo depende apenas do produto \\(R \\times C\\), e n\u00e3o da tens\u00e3o de alimenta\u00e7\u00e3o. Dobrar o resistor ou o capacitor dobra o tempo de resposta do circuito. \u00c9 por isso que as redes RC s\u00e3o o bloco construtivo padr\u00e3o para temporizadores, filtros, circuitos de debounce, formata\u00e7\u00e3o de pulsos e filtragem em fontes de alimenta\u00e7\u00e3o.<\/p>\n<p>Interpretar os n\u00fameros dos marcos \u00e9 simples. Um capacitor passa da metade da carga em 0,69\u03c4, atinge 90% em cerca de 2,3\u03c4, 95% em 3\u03c4 e 99% em 4,6\u03c4. Se voc\u00ea est\u00e1 projetando um atraso que precisa disparar em um limiar espec\u00edfico, use a f\u00f3rmula \\(t_f\\): por exemplo, um temporizador no estilo 555 que comuta em dois ter\u00e7os da tens\u00e3o de alimenta\u00e7\u00e3o precisa de cerca de 1,1\u03c4 por ciclo. Os mesmos marcos, de forma espelhada, valem para a descarga: ap\u00f3s 1\u03c4 o capacitor mant\u00e9m 36,8% da carga, ap\u00f3s 3\u03c4 apenas 5% e ap\u00f3s 5\u03c4 cerca de 0,7%.<\/p>\n<h2>Valores t\u00edpicos dos marcos<\/h2>\n<table>\n<thead>\n<tr>\n<th>Tempo decorrido<\/th>\n<th>Carga (% do valor final)<\/th>\n<th>Descarga (% restante)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>0,69\u03c4<\/td>\n<td>50%<\/td>\n<td>50%<\/td>\n<\/tr>\n<tr>\n<td>1\u03c4<\/td>\n<td>63,2%<\/td>\n<td>36,8%<\/td>\n<\/tr>\n<tr>\n<td>2\u03c4<\/td>\n<td>86,5%<\/td>\n<td>13,5%<\/td>\n<\/tr>\n<tr>\n<td>3\u03c4<\/td>\n<td>95,0%<\/td>\n<td>5,0%<\/td>\n<\/tr>\n<tr>\n<td>4\u03c4<\/td>\n<td>98,2%<\/td>\n<td>1,8%<\/td>\n<\/tr>\n<tr>\n<td>5\u03c4<\/td>\n<td>99,3%<\/td>\n<td>0,7%<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>Premissas, limita\u00e7\u00f5es e dicas<\/h2>\n<ul>\n<li><strong>Componentes ideais:<\/strong> o c\u00e1lculo assume um resistor e um capacitor perfeitos. Capacitores reais t\u00eam corrente de fuga e resist\u00eancia s\u00e9rie equivalente (ESR), que alteram levemente o comportamento em tempos longos, e resistores reais t\u00eam uma pequena indut\u00e2ncia parasita que s\u00f3 importa em velocidades muito altas.<\/li>\n<li><strong>Imped\u00e2ncia de fonte nula:<\/strong> a alimenta\u00e7\u00e3o \u00e9 tratada como uma fonte de tens\u00e3o ideal. Se a fonte tiver resist\u00eancia interna significativa, some-a a R; se o capacitor descarregar em uma carga, o R relevante \u00e9 a resist\u00eancia de Th\u00e9venin vista pelo capacitor.<\/li>\n<li><strong>Consist\u00eancia de unidades:<\/strong> mantenha R em ohms e C em farads para obter \u03c4 em segundos. A calculadora faz a convers\u00e3o de unidades automaticamente, o que evita o erro cl\u00e1ssico de misturar k\u03a9 com \u00b5F manualmente (10 k\u03a9 \u00d7 100 \u00b5F = 1 s, e n\u00e3o 1 ms ou 1 ks).<\/li>\n<li><strong>Toler\u00e2ncia pr\u00e1tica:<\/strong> capacitores eletrol\u00edticos costumam ter toler\u00e2ncias de \u00b120% ou mais, ent\u00e3o a temporiza\u00e7\u00e3o medida pode se desviar visivelmente do valor calculado. Para temporiza\u00e7\u00e3o de precis\u00e3o, use capacitores de filme com toler\u00e2ncia estreita ou ajuste o resistor.<\/li>\n<li><strong>S\u00e9rie versus paralelo:<\/strong> se v\u00e1rios resistores ou capacitores formarem a rede, reduza-os primeiro \u2014 por exemplo com a calculadora de <a href=\"https:\/\/wpcalc.com\/pt\/engenharia\/resistencia-em-paralelo\/\">Resist\u00eancia em paralelo<\/a> \u2014 e depois calcule \u03c4 com o R e o C equivalentes.<\/li>\n<\/ul>\n<h2>Ferramentas relacionadas<\/h2>\n<p>Para outros c\u00e1lculos no n\u00edvel de componentes, experimente a calculadora de <a href=\"https:\/\/wpcalc.com\/pt\/engenharia\/diodo-zener\/\">Resistor para diodo Zener<\/a> para dimensionar um resistor limitador de corrente, ou as calculadoras de <a href=\"https:\/\/wpcalc.com\/pt\/engenharia\/indutancia-em-serie\/\">Indut\u00e2ncia em s\u00e9rie<\/a> e <a href=\"https:\/\/wpcalc.com\/pt\/engenharia\/indutancia-em-paralelo\/\">Indut\u00e2ncia em paralelo<\/a> quando seu circuito partir para o lado indutivo (onde a grandeza an\u00e1loga \u00e9 L\/R).<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Informe qualquer valor de resist\u00eancia e capacit\u00e2ncia e obtenha instantaneamente a constante de tempo RC (\u03c4), al\u00e9m dos tempos de carga e descarga para 50%, 90%, 95% e 99% da tens\u00e3o final.<\/p>\n","protected":false},"author":3168,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[6],"tags":[82],"class_list":["post-2184","post","type-post","status-publish","format-standard","hentry","category-engenharia","tag-circuitos"],"acf":[],"_links":{"self":[{"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/posts\/2184","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/users\/3168"}],"replies":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/comments?post=2184"}],"version-history":[{"count":0,"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/posts\/2184\/revisions"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/media?parent=2184"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/categories?post=2184"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/tags?post=2184"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}