{"id":855882,"date":"2026-02-14T09:20:42","date_gmt":"2026-02-14T09:20:42","guid":{"rendered":"https:\/\/elektrobox.ch\/?page_id=855882"},"modified":"2026-05-24T07:05:45","modified_gmt":"2026-05-24T07:05:45","slug":"electronics-calulator","status":"publish","type":"page","link":"https:\/\/elektrobox.ch\/index.php\/electronics-calulator\/","title":{"rendered":"Electronics Calulator"},"content":{"rendered":"      <section class=\"ecw-page\" aria-labelledby=\"ecw-page-title\">\n        <header class=\"ecw-hero\">\n          <div class=\"ecw-hero__content\">\n            <p class=\"ecw-kicker\">ElektroBox Tool<\/p>\n            <h1 id=\"ecw-page-title\">Electronics Calculator for Circuit Design and Learning<\/h1>\n            <p class=\"ecw-hero__lead\">Use this browser-based electronics calculator for common circuit calculations: Ohm\u2019s law, power, voltage dividers, LED resistors, resistor networks, RC filters, reactance, op-amp gain and resistor color codes.<\/p>\n            <div class=\"ecw-hero__meta\" aria-label=\"Tool highlights\">\n              <span>No login required<\/span>\n              <span>Runs in the browser<\/span>\n              <span>Useful for electronics projects<\/span>\n            <\/div>\n          <\/div>\n        <\/header>\n\n        <div class=\"ecw-layout\">\n          <main class=\"ecw-layout__main\">\n    \n    <div class=\"ecw\" data-default-tab=\"ohm\">\n      <div class=\"ecw-shell\">\n        <div class=\"ecw-sidebar\" role=\"navigation\" aria-label=\"Electronic calculator navigation\">\n          <div class=\"ecw-title\">Electronic Calculator<\/div>\n          <button type=\"button\" class=\"ecw-nav\" data-tab=\"ohm\"><span>Ohm\u2019s law & power<\/span><\/button>\n          <button type=\"button\" class=\"ecw-nav\" data-tab=\"divider\"><span>Voltage divider<\/span><\/button>\n          <button type=\"button\" class=\"ecw-nav\" data-tab=\"led\"><span>LED resistor<\/span><\/button>\n          <button type=\"button\" class=\"ecw-nav\" data-tab=\"network\"><span>Series \/ parallel resistors<\/span><\/button>\n          <button type=\"button\" class=\"ecw-nav\" data-tab=\"rc\"><span>RC time constant & cutoff<\/span><\/button>\n          <button type=\"button\" class=\"ecw-nav\" data-tab=\"reactance\"><span>Capacitive \/ inductive reactance<\/span><\/button>\n          <button type=\"button\" class=\"ecw-nav\" data-tab=\"opamp\"><span>Op-amp gain<\/span><\/button>\n          <button type=\"button\" class=\"ecw-nav\" data-tab=\"resistor\"><span>Resistor color code<\/span><\/button>\n        <\/div>\n\n        <div class=\"ecw-main\" role=\"region\" aria-label=\"Electronic calculator content\">\n          <section class=\"ecw-panel\" data-tab=\"ohm\">\n            <h3>Ohm\u2019s law & power<\/h3>\n            <p class=\"ecw-sub\">Enter any two values. The calculator solves voltage, current, resistance, and power.<\/p>\n            <div class=\"ecw-card\">\n              <div class=\"ecw-grid4\">\n                <div class=\"ecw-field\"><label>Voltage V (V)<\/label><input class=\"ecw-ohm-v\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"e.g. 5\" \/><\/div>\n                <div class=\"ecw-field\"><label>Current I (A)<\/label><input class=\"ecw-ohm-i\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"e.g. 0.02\" \/><\/div>\n                <div class=\"ecw-field\"><label>Resistance R (\u03a9)<\/label><input class=\"ecw-ohm-r\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"e.g. 250\" \/><\/div>\n                <div class=\"ecw-field\"><label>Power P (W)<\/label><input class=\"ecw-ohm-p\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"e.g. 0.1\" \/><\/div>\n              <\/div>\n              <div class=\"ecw-row ecw-row-actions\">\n                <button type=\"button\" class=\"ecw-btn ecw-ohm-calc\">Calculate<\/button>\n                <button type=\"button\" class=\"ecw-btn ecw-btn-ghost ecw-ohm-clear\">Reset<\/button>\n                <div class=\"ecw-hint ecw-ohm-hint\" aria-live=\"polite\"><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ecw-explain\">\n              <div class=\"ecw-explain-grid\">\n                <div class=\"ecw-explain-text\">\n                  <h4>How this calculation works<\/h4>\n                  <p>Ohm\u2019s law links voltage, current, and resistance. Power is then derived from the solved values.<\/p>\n                  <ul>\n                    <li><strong>V = I \u00d7 R<\/strong><\/li>\n                    <li><strong>I = V \/ R<\/strong><\/li>\n                    <li><strong>R = V \/ I<\/strong><\/li>\n                    <li><strong>P = V \u00d7 I = I\u00b2R = V\u00b2\/R<\/strong><\/li>\n                  <\/ul>\n                  <p>Enter any two known quantities. The calculator uses the matching formula set to compute the missing values.<\/p>\n                <\/div>\n              <\/div>\n            <\/div>\n          <\/section>\n\n          <section class=\"ecw-panel\" data-tab=\"divider\">\n            <h3>Voltage divider<\/h3>\n            <p class=\"ecw-sub\">Calculates an unloaded two-resistor voltage divider.<\/p>\n            <div class=\"ecw-card\">\n              <div class=\"ecw-grid3\">\n                <div class=\"ecw-field\"><label>Input voltage Vin (V)<\/label><input class=\"ecw-div-vin\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"e.g. 12\" \/><\/div>\n                <div class=\"ecw-field\"><label>Top resistor R1 (\u03a9)<\/label><input class=\"ecw-div-r1\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"e.g. 10000\" \/><\/div>\n                <div class=\"ecw-field\"><label>Bottom resistor R2 (\u03a9)<\/label><input class=\"ecw-div-r2\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"e.g. 4700\" \/><\/div>\n              <\/div>\n              <div class=\"ecw-grid3 ecw-result-grid\">\n                <div class=\"ecw-field\"><label>Vout (V)<\/label><input class=\"ecw-div-vout\" type=\"text\" readonly \/><\/div>\n                <div class=\"ecw-field\"><label>Divider current (A)<\/label><input class=\"ecw-div-i\" type=\"text\" readonly \/><\/div>\n                <div class=\"ecw-field\"><label>Ratio Vout\/Vin<\/label><input class=\"ecw-div-ratio\" type=\"text\" readonly \/><\/div>\n              <\/div>\n              <div class=\"ecw-row ecw-row-actions\">\n                <button type=\"button\" class=\"ecw-btn ecw-div-calc\">Calculate<\/button>\n                <div class=\"ecw-hint ecw-div-hint\" aria-live=\"polite\"><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ecw-explain\">\n              <div class=\"ecw-explain-grid\">\n                <div class=\"ecw-explain-text\">\n                  <h4>How this calculation works<\/h4>\n                  <p>A voltage divider creates a lower output voltage from a higher input voltage using two resistors in series.<\/p>\n                  <ul>\n                    <li><strong>Output voltage:<\/strong> Vout = Vin \u00d7 R2 \/ (R1 + R2)<\/li>\n                    <li><strong>Divider current:<\/strong> I = Vin \/ (R1 + R2)<\/li>\n                    <li><strong>Voltage ratio:<\/strong> Vout\/Vin = R2 \/ (R1 + R2)<\/li>\n                  <\/ul>\n                  <p>This simplified calculator assumes that the output is not loaded by another circuit. For accurate results, the input impedance of the next circuit should be much higher than R2.<\/p>\n                <\/div>\n              <\/div>\n            <\/div>\n          <\/section>\n\n          <section class=\"ecw-panel\" data-tab=\"led\">\n            <h3>LED series resistor<\/h3>\n            <p class=\"ecw-sub\">Calculates the series resistor and resistor power for one LED.<\/p>\n            <div class=\"ecw-card\">\n              <div class=\"ecw-grid3\">\n                <div class=\"ecw-field\"><label>Supply voltage Vs (V)<\/label><input class=\"ecw-led-vs\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"e.g. 5\" \/><\/div>\n                <div class=\"ecw-field\"><label>LED forward voltage Vf (V)<\/label><input class=\"ecw-led-vf\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"e.g. 2.1\" \/><\/div>\n                <div class=\"ecw-field\"><label>LED current (mA)<\/label><input class=\"ecw-led-imA\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"e.g. 20\" \/><\/div>\n              <\/div>\n              <div class=\"ecw-grid3 ecw-result-grid\">\n                <div class=\"ecw-field\"><label>Series resistor (\u03a9)<\/label><input class=\"ecw-led-r\" type=\"text\" readonly \/><\/div>\n                <div class=\"ecw-field\"><label>Resistor power (W)<\/label><input class=\"ecw-led-p\" type=\"text\" readonly \/><\/div>\n                <div class=\"ecw-field\"><label>Suggested rating<\/label><input class=\"ecw-led-rating\" type=\"text\" readonly \/><\/div>\n              <\/div>\n              <div class=\"ecw-row ecw-row-actions\">\n                <button type=\"button\" class=\"ecw-btn ecw-led-calc\">Calculate<\/button>\n                <div class=\"ecw-hint ecw-led-hint\" aria-live=\"polite\"><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ecw-explain\">\n              <div class=\"ecw-explain-grid\">\n                <div class=\"ecw-explain-text\">\n                  <h4>How this calculation works<\/h4>\n                  <p>The resistor drops the voltage that is left over after the LED forward voltage is subtracted from the supply.<\/p>\n                  <ul>\n                    <li><strong>LED forward voltage Vf:<\/strong> the voltage drop across the LED when it is on. Typical values are about 1.8\u20132.2 V for red LEDs and about 2.8\u20133.4 V for many blue\/white LEDs.<\/li>\n                    <li><strong>LED current:<\/strong> the desired operating current through the LED. Small indicator LEDs often use 5\u201320 mA.<\/li>\n                    <li><strong>Resistor voltage:<\/strong> VR = Vs \u2212 Vf<\/li>\n                    <li><strong>Series resistor:<\/strong> R = VR \/ I<\/li>\n                    <li><strong>Resistor power:<\/strong> P = VR \u00d7 I<\/li>\n                  <\/ul>\n                  <p>The suggested power rating is chosen above the computed resistor dissipation for a safer design margin.<\/p>\n                <\/div>\n              <\/div>\n            <\/div>\n          <\/section>\n\n          <section class=\"ecw-panel\" data-tab=\"network\">\n            <h3>Series \/ parallel resistors<\/h3>\n            <p class=\"ecw-sub\">Enter resistor values in ohms, separated by commas, spaces, semicolons, or line breaks.<\/p>\n            <div class=\"ecw-card\">\n              <div class=\"ecw-field ecw-field-grow\">\n                <label>Resistors (\u03a9)<\/label>\n                <textarea class=\"ecw-net-values\" rows=\"4\" maxlength=\"500\" placeholder=\"e.g. 1000, 2200, 4700\"><\/textarea>\n              <\/div>\n              <div class=\"ecw-grid3 ecw-result-grid\">\n                <div class=\"ecw-field\"><label>Series equivalent<\/label><input class=\"ecw-net-series\" type=\"text\" readonly \/><\/div>\n                <div class=\"ecw-field\"><label>Parallel equivalent<\/label><input class=\"ecw-net-parallel\" type=\"text\" readonly \/><\/div>\n                <div class=\"ecw-field\"><label>Number of resistors<\/label><input class=\"ecw-net-count\" type=\"text\" readonly \/><\/div>\n              <\/div>\n              <div class=\"ecw-row ecw-row-actions\">\n                <button type=\"button\" class=\"ecw-btn ecw-net-calc\">Calculate<\/button>\n                <div class=\"ecw-hint ecw-net-hint\" aria-live=\"polite\"><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ecw-explain\">\n              <div class=\"ecw-explain-grid\">\n                <div class=\"ecw-explain-text\">\n                  <h4>How this calculation works<\/h4>\n                  <ul>\n                    <li><strong>Series:<\/strong> Req = R1 + R2 + R3 + ...<\/li>\n                    <li><strong>Parallel:<\/strong> 1\/Req = 1\/R1 + 1\/R2 + 1\/R3 + ...<\/li>\n                  <\/ul>\n                  <p>Series resistors add directly. Parallel resistors always produce an equivalent value lower than the smallest individual resistor.<\/p>\n                <\/div>\n              <\/div>\n            <\/div>\n          <\/section>\n\n          <section class=\"ecw-panel\" data-tab=\"rc\">\n            <h3>RC time constant & cutoff frequency<\/h3>\n            <p class=\"ecw-sub\">Calculates \u03c4 = R \u00b7 C and f<sub>c<\/sub> = 1 \/ (2\u03c0RC).<\/p>\n            <div class=\"ecw-card\">\n              <div class=\"ecw-grid4\">\n                <div class=\"ecw-field\"><label>Resistance R (\u03a9)<\/label><input class=\"ecw-rc-r\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"e.g. 10000\" \/><\/div>\n                <div class=\"ecw-field\"><label>Capacitance C<\/label><input class=\"ecw-rc-c\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"e.g. 100\" \/><\/div>\n                <div class=\"ecw-field\"><label>Capacitance unit<\/label><select class=\"ecw-rc-cunit\"><option value=\"1\">F<\/option><option value=\"0.001\">mF<\/option><option value=\"0.000001\" selected>\u00b5F<\/option><option value=\"0.000000001\">nF<\/option><option value=\"0.000000000001\">pF<\/option><\/select><\/div>\n                <div class=\"ecw-field\"><label>Target charge (%)<\/label><input class=\"ecw-rc-target\" type=\"text\" inputmode=\"decimal\" maxlength=\"8\" value=\"100\" \/><\/div>\n              <\/div>\n              <div class=\"ecw-grid4 ecw-result-grid\">\n                <div class=\"ecw-field\"><label>Time constant \u03c4 (s)<\/label><input class=\"ecw-rc-tau\" type=\"text\" readonly \/><\/div>\n                <div class=\"ecw-field\"><label>Cutoff frequency fc (Hz)<\/label><input class=\"ecw-rc-fc\" type=\"text\" readonly \/><\/div>\n                <div class=\"ecw-field\"><label>Charge time to target (s)<\/label><input class=\"ecw-rc-tcharge\" type=\"text\" readonly \/><\/div>\n                <div class=\"ecw-field\"><label>After 5\u03c4<\/label><input class=\"ecw-rc-five\" type=\"text\" readonly \/><\/div>\n              <\/div>\n              <div class=\"ecw-row ecw-row-actions\">\n                <button type=\"button\" class=\"ecw-btn ecw-rc-calc\">Calculate<\/button>\n                <div class=\"ecw-hint ecw-rc-hint\" aria-live=\"polite\"><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ecw-explain\">\n              <div class=\"ecw-explain-grid\">\n                <div class=\"ecw-explain-text\">\n                  <h4>How this calculation works<\/h4>\n                  <ul>\n                    <li><strong>Time constant:<\/strong> \u03c4 = R \u00d7 C<\/li>\n                    <li><strong>Cutoff frequency:<\/strong> fc = 1 \/ (2\u03c0RC)<\/li>\n                    <li><strong>Charging law:<\/strong> Vc(t) = Vs \u00d7 (1 \u2212 e<sup>\u2212t\/\u03c4<\/sup>)<\/li>\n                  <\/ul>\n                  <p>At <strong>1\u03c4<\/strong>, a charging capacitor reaches about <strong>63.2%<\/strong> of its final voltage. Exact <strong>100%<\/strong> charge is theoretical because the capacitor approaches the final voltage asymptotically. In practice, <strong>5\u03c4<\/strong> is commonly treated as almost fully charged, about <strong>99.3%<\/strong>.<\/p>\n                  <p>The <strong>cutoff frequency<\/strong> is the frequency where a simple RC filter output has dropped to about <strong>70.7%<\/strong> of its low-frequency value, also called the <strong>\u22123 dB point<\/strong>.<\/p>\n                <\/div>\n              <\/div>\n            <\/div>\n          <\/section>\n\n          <section class=\"ecw-panel\" data-tab=\"reactance\">\n            <h3>Capacitive \/ inductive reactance<\/h3>\n            <p class=\"ecw-sub\">Calculates Xc = 1 \/ (2\u03c0fC) and XL = 2\u03c0fL.<\/p>\n            <div class=\"ecw-card\">\n              <div class=\"ecw-grid4\">\n                <div class=\"ecw-field\"><label>Frequency f (Hz)<\/label><input class=\"ecw-x-f\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"e.g. 1000\" \/><\/div>\n                <div class=\"ecw-field\"><label>Capacitance C<\/label><input class=\"ecw-x-c\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"e.g. 100\" \/><\/div>\n                <div class=\"ecw-field\"><label>C unit<\/label><select class=\"ecw-x-cunit\"><option value=\"1\">F<\/option><option value=\"0.001\">mF<\/option><option value=\"0.000001\" selected>\u00b5F<\/option><option value=\"0.000000001\">nF<\/option><option value=\"0.000000000001\">pF<\/option><\/select><\/div>\n                <div class=\"ecw-field\"><label>Inductance L<\/label><input class=\"ecw-x-l\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"e.g. 10\" \/><\/div>\n              <\/div>\n              <div class=\"ecw-grid3\">\n                <div class=\"ecw-field\"><label>L unit<\/label><select class=\"ecw-x-lunit\"><option value=\"1\">H<\/option><option value=\"0.001\" selected>mH<\/option><option value=\"0.000001\">\u00b5H<\/option><option value=\"0.000000001\">nH<\/option><\/select><\/div>\n                <div class=\"ecw-field\"><label>Capacitive reactance Xc (\u03a9)<\/label><input class=\"ecw-x-xc\" type=\"text\" readonly \/><\/div>\n                <div class=\"ecw-field\"><label>Inductive reactance XL (\u03a9)<\/label><input class=\"ecw-x-xl\" type=\"text\" readonly \/><\/div>\n              <\/div>\n              <div class=\"ecw-row ecw-row-actions\">\n                <button type=\"button\" class=\"ecw-btn ecw-x-calc\">Calculate<\/button>\n                <div class=\"ecw-hint ecw-x-hint\" aria-live=\"polite\"><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ecw-explain\">\n              <div class=\"ecw-explain-grid\">\n                <div class=\"ecw-explain-text\">\n                  <h4>How this calculation works<\/h4>\n                  <ul>\n                    <li><strong>Capacitor:<\/strong> Xc = 1 \/ (2\u03c0fC)<\/li>\n                    <li><strong>Inductor:<\/strong> XL = 2\u03c0fL<\/li>\n                  <\/ul>\n                  <p>As frequency increases, <strong>capacitive reactance decreases<\/strong>, while <strong>inductive reactance increases<\/strong>. These values behave like frequency-dependent AC resistance.<\/p>\n                <\/div>\n              <\/div>\n            <\/div>\n          <\/section>\n\n          <section class=\"ecw-panel\" data-tab=\"opamp\">\n            <h3>Op-amp gain<\/h3>\n            <p class=\"ecw-sub\">Calculates non-inverting and inverting amplifier gain from feedback and input resistors.<\/p>\n            <div class=\"ecw-card\">\n              <div class=\"ecw-grid4\">\n                <div class=\"ecw-field\"><label>Input resistor Rin \/ Rg (\u03a9)<\/label><input class=\"ecw-op-rin\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"e.g. 10000\" \/><\/div>\n                <div class=\"ecw-field\"><label>Feedback resistor Rf (\u03a9)<\/label><input class=\"ecw-op-rf\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"e.g. 47000\" \/><\/div>\n                <div class=\"ecw-field\"><label>Input voltage Vin (optional)<\/label><input class=\"ecw-op-vin\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"optional\" \/><\/div>\n                <div class=\"ecw-field\"><label>Supply limit \u00b1V (optional)<\/label><input class=\"ecw-op-vlim\" type=\"text\" inputmode=\"decimal\" maxlength=\"24\" placeholder=\"optional\" \/><\/div>\n              <\/div>\n              <div class=\"ecw-grid4 ecw-result-grid\">\n                <div class=\"ecw-field\"><label>Non-inverting gain<\/label><input class=\"ecw-op-noninv\" type=\"text\" readonly \/><\/div>\n                <div class=\"ecw-field\"><label>Inverting gain<\/label><input class=\"ecw-op-inv\" type=\"text\" readonly \/><\/div>\n                <div class=\"ecw-field\"><label>Non-inverting Vout<\/label><input class=\"ecw-op-vout-noninv\" type=\"text\" readonly \/><\/div>\n                <div class=\"ecw-field\"><label>Inverting Vout<\/label><input class=\"ecw-op-vout-inv\" type=\"text\" readonly \/><\/div>\n              <\/div>\n              <div class=\"ecw-row ecw-row-actions\">\n                <button type=\"button\" class=\"ecw-btn ecw-op-calc\">Calculate<\/button>\n                <div class=\"ecw-hint ecw-op-hint\" aria-live=\"polite\"><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ecw-explain\">\n              <div class=\"ecw-explain-grid\">\n                <div class=\"ecw-explain-text\">\n                  <h4>How this calculation works<\/h4>\n                  <ul>\n                    <li><strong>Non-inverting gain:<\/strong> Av = 1 + Rf \/ Rg<\/li>\n                    <li><strong>Inverting gain:<\/strong> Av = \u2212Rf \/ Rin<\/li>\n                  <\/ul>\n                  <p>If you enter an input voltage, the calculator also estimates the output voltage. If a supply limit is entered, the displayed output is clipped to the chosen \u00b1 supply rail.<\/p>\n                <\/div>\n              <\/div>\n            <\/div>\n          <\/section>\n\n          <section class=\"ecw-panel\" data-tab=\"resistor\">\n            <h3>Resistor color code<\/h3>\n            <p class=\"ecw-sub\">Supports 3, 4, 5, and 6 band resistors.<\/p>\n            <div class=\"ecw-card\">\n              <div class=\"ecw-row\">\n                <div class=\"ecw-field\"><label>Number of bands<\/label><select class=\"ecw-res-bands\"><option value=\"3\">3 bands<\/option><option value=\"4\" selected>4 bands<\/option><option value=\"5\">5 bands<\/option><option value=\"6\">6 bands<\/option><\/select><\/div>\n              <\/div>\n              <div class=\"ecw-row ecw-res-dynamic\" style=\"margin-top: 12px;\"><\/div>\n              <div class=\"ecw-row ecw-row-actions\">\n                <div class=\"ecw-field ecw-field-grow\"><label>Result<\/label><input class=\"ecw-res-out\" type=\"text\" readonly \/><\/div>\n                <button type=\"button\" class=\"ecw-btn ecw-res-copy\">Copy<\/button>\n                <div class=\"ecw-hint ecw-res-hint\" aria-live=\"polite\"><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ecw-explain\">\n              <div class=\"ecw-explain-grid\">\n                <div class=\"ecw-explain-text\">\n                  <h4>How this calculation works<\/h4>\n                  <p>The color bands encode the significant digits, multiplier, tolerance, and optionally the temperature coefficient.<\/p>\n                  <ul>\n                    <li><strong>3 bands:<\/strong> 2 digits + multiplier<\/li>\n                    <li><strong>4 bands:<\/strong> 2 digits + multiplier + tolerance<\/li>\n                    <li><strong>5 bands:<\/strong> 3 digits + multiplier + tolerance<\/li>\n                    <li><strong>6 bands:<\/strong> 3 digits + multiplier + tolerance + tempco<\/li>\n                  <\/ul>\n                  <p>Example: <strong>brown, black, red, gold<\/strong> means <strong>1, 0, \u00d7100, \u00b15%<\/strong>, which equals <strong>1 k\u03a9 \u00b15%<\/strong>.<\/p>\n                <\/div>\n              <\/div>\n            <\/div>\n          <\/section>\n        <\/div>\n      <\/div>\n    <\/div>\n\n              <aside class=\"ecw-layout__aside\" aria-label=\"Electronics calculator notes\">\n            <div class=\"ecw-side-card\"><h2>Best for<\/h2><ul><li>Electronics learning<\/li><li>Arduino and ESP32 projects<\/li><li>Quick circuit checks<\/li><li>Maker documentation<\/li><\/ul><\/div>\n            <div class=\"ecw-side-card\"><h2>Before building<\/h2><p>Always check component limits, polarity, voltage rating, current rating and expected heat dissipation before powering a real circuit.<\/p><\/div>\n          <\/aside>\n\n          <section class=\"ecw-content-section\" aria-labelledby=\"ecw-how-title\">\n            <p class=\"ecw-kicker\">How to use it<\/p>\n            <h2 id=\"ecw-how-title\">Select the calculator that matches your circuit question<\/h2>\n            <p>Choose a tool from the left menu, enter the known values and press <strong>Calculate<\/strong>. The calculator keeps the formulas visible below each tool, so the result is easier to understand and verify instead of being only a black-box number.<\/p>\n            <div class=\"ecw-info-grid\">\n              <article class=\"ecw-info-card\"><h3>Start with units<\/h3><p>Most fields use base SI units such as volt, ampere, ohm, farad and hertz. Where smaller values are common, unit selectors are included for \u00b5F, nF, pF, mH and \u00b5H.<\/p><\/article>\n              <article class=\"ecw-info-card\"><h3>Check practical limits<\/h3><p>For LED resistors, op-amps and dividers, the result should still be checked against component ratings, power dissipation, tolerances and the real load connected to the circuit.<\/p><\/article>\n              <article class=\"ecw-info-card\"><h3>Use it for learning<\/h3><p>Each tool includes the underlying formula, making the page suitable for project work, homework checks and quick electronics reference notes.<\/p><\/article>\n            <\/div>\n          <\/section>\n\n          <section class=\"ecw-content-section\" aria-labelledby=\"ecw-examples-title\">\n            <p class=\"ecw-kicker\">Typical examples<\/p>\n            <h2 id=\"ecw-examples-title\">Common electronics calculations<\/h2>\n            <div class=\"ecw-example-grid\">\n              <article class=\"ecw-example-card\"><span>Ohm\u2019s law<\/span><code>5 V \/ 0.02 A = 250 \u03a9<\/code><p>Useful for checking current draw, resistor values and power dissipation.<\/p><\/article>\n              <article class=\"ecw-example-card\"><span>Voltage divider<\/span><code>Vout = Vin \u00d7 R2 \/ (R1 + R2)<\/code><p>Useful for sensor scaling and simple reference voltages when the output load is high impedance.<\/p><\/article>\n              <article class=\"ecw-example-card\"><span>RC cutoff<\/span><code>fc = 1 \/ (2\u03c0RC)<\/code><p>Useful for first-order low-pass and high-pass filter estimates.<\/p><\/article>\n              <article class=\"ecw-example-card\"><span>LED resistor<\/span><code>R = (Vs \u2212 Vf) \/ I<\/code><p>Useful for selecting a safe series resistor and estimating resistor wattage.<\/p><\/article>\n            <\/div>\n          <\/section>\n\n          <section class=\"ecw-content-section\" aria-labelledby=\"ecw-reference-title\">\n            <p class=\"ecw-kicker\">Reference<\/p>\n            <h2 id=\"ecw-reference-title\">What each electronics calculator is for<\/h2>\n            <div class=\"ecw-table-wrap\">\n              <table class=\"ecw-table\">\n                <thead><tr><th scope=\"col\">Tool<\/th><th scope=\"col\">Use it for<\/th><th scope=\"col\">Important note<\/th><\/tr><\/thead>\n                <tbody>\n                  <tr><td>Ohm\u2019s law & power<\/td><td>Voltage, current, resistance and power relationships<\/td><td>Power results should be checked against the component wattage rating.<\/td><\/tr>\n                  <tr><td>Voltage divider<\/td><td>Estimating unloaded divider output voltage<\/td><td>A real load changes Vout; use a buffer or lower resistor values if needed.<\/td><\/tr>\n                  <tr><td>LED resistor<\/td><td>Calculating a series resistor for one LED<\/td><td>Use the LED datasheet for forward voltage and recommended current.<\/td><\/tr>\n                  <tr><td>Resistor network<\/td><td>Series and parallel equivalent resistance<\/td><td>All resistor values must be positive and in the same unit.<\/td><\/tr>\n                  <tr><td>RC time constant<\/td><td>Charge timing and first-order filter cutoff<\/td><td>Capacitor tolerance can strongly affect the real timing result.<\/td><\/tr>\n                  <tr><td>Reactance<\/td><td>Frequency-dependent impedance of capacitors and inductors<\/td><td>Real parts also have ESR, leakage, parasitic capacitance and tolerance.<\/td><\/tr>\n                  <tr><td>Op-amp gain<\/td><td>Ideal inverting and non-inverting gain estimates<\/td><td>Real output swing depends on supply voltage, load and the op-amp type.<\/td><\/tr>\n                  <tr><td>Resistor color code<\/td><td>Reading 3, 4, 5 and 6 band resistors<\/td><td>Measure with a multimeter when precision matters.<\/td><\/tr>\n                <\/tbody>\n              <\/table>\n            <\/div>\n          <\/section>\n\n          <section class=\"ecw-content-section\" aria-labelledby=\"ecw-faq-title\">\n            <p class=\"ecw-kicker\">FAQ<\/p>\n            <h2 id=\"ecw-faq-title\">Electronics calculator questions<\/h2>\n            <div class=\"ecw-faq-list\">\n              <details><summary>Can I use this calculator for real circuit design?<\/summary><p>Yes, for first estimates and quick checks. For final designs, verify the result with datasheets, tolerances, thermal limits and measurements on the real circuit.<\/p><\/details>\n              <details><summary>Why do some results differ from measurements?<\/summary><p>Real components have tolerance, temperature drift and parasitic effects. A resistor marked 10 k\u03a9 may not be exactly 10 k\u03a9, and capacitors can vary significantly depending on type and voltage bias.<\/p><\/details>\n              <details><summary>Why is the voltage divider marked as unloaded?<\/summary><p>The formula assumes that no current is drawn from the output node. When another circuit is connected, its input impedance appears in parallel with R2 and changes the output voltage.<\/p><\/details>\n              <details><summary>What does 5\u03c4 mean for an RC circuit?<\/summary><p>After five time constants, a charging capacitor is practically close to its final value, about 99.3%, although mathematically it approaches the final voltage asymptotically.<\/p><\/details>\n            <\/div>\n          <\/section>\n        <\/main>\n      <\/div>\n    <\/section>\n        \n\n\n\n<p class=\"wp-block-paragraph\">Use this electronics calculator to solve common circuit values quickly. Calculate Ohm\u2019s law, power, voltage dividers, LED resistors, series and parallel resistors, RC time constants, reactance, op-amp gain, and resistor color codes.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Use this electronics calculator to solve common circuit values quickly. Calculate Ohm\u2019s law, power, voltage dividers, LED resistors, series and parallel resistors, RC time constants, reactance, op-amp gain, and resistor color codes.<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-855882","page","type-page","status-publish","hentry"],"blocksy_meta":{"styles_descriptor":{"styles":{"desktop":"","tablet":"","mobile":""},"google_fonts":[],"version":7}},"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.1 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Electronics Calulator - ElektroBox<\/title>\n<meta name=\"description\" content=\"Use the ElektroBox electronics calculator for Ohm\u2019s law, power, voltage dividers, LED resistors, RC time constants, and resistor color codes.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/elektrobox.ch\/index.php\/electronics-calulator\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Electronics Calulator - 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