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Buck Converter Calculator

Calculate Ohm's law (V=IR), voltage dividers, LED current-limiting resistors, RC/RLC resonant frequency, RC filter cutoff, and PCB trace width for buck converter.

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Input Circuit Parameters

Enter supply voltage, resistance, inductance, or capacitance.

Calculated Current (I) / Output Voltage

25.53 mA
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Ohm's Law Foundation

Current flowing through a conductor between two points is directly proportional to voltage across the points: I = V / R (1 Ampere = 1 Volt / 1 Ohm).

Calculation Methodology & Details

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Formula

Ohm's Law: V = I × R Voltage Divider: V_out = V_in × [R₂ / (R₁ + R₂)] LED Resistor: R = (V_supply - V_forward) / I_led RC Filter Cutoff: f_c = 1 / (2π × R × C) Resonant Frequency: f_0 = 1 / (2π √(L × C))

Applies Kirchhoff's current/voltage laws (KCL/KVL), IPC-2221 PCB trace current capacity, and 555 timer astable multivibrator duty cycle formulas.

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Important Disclaimer

Calculations assume nominal component values without component tolerance derating (±5% resistor bands) or temperature coefficient drifts.

How to Calculate Step-by-Step

Follow these steps to complete the calculation:

1

Step 1

Enter input voltage V_in or LED forward voltage V_f (e.g. 2.0V for Red, 3.2V for Blue/White).

2

Step 2

Input component values R (Ohms Ω), C (Microfarads μF), or L (Millihenries mH).

3

Step 3

View current output in mA, LED current-limiting resistor wattage rating, 3dB cutoff frequency (Hz), or PCB trace width in mils/mm.

Detailed Insights & Expert Guide

ℹ️ About this Calculation

The Buck Converter Calculator solves electronic circuit Ohm's law, voltage/current dividers, LED series resistors, 555 timer pulse frequencies, op-amp gain, and PCB copper trace current sizing.

Variable Glossary

Input

Voltage (V)

Electrical potential difference between two circuit points measured in Volts.

Parameter

Resistance (R)

Opposition to electric current flow measured in Ohms Ω (P = I²R = V²/R).

FAQ

How is an LED series resistor calculated?
Resistor R = (V_supply - V_led) / I_led. For example, powered from 5V with a 2.0V red LED at 20mA (0.020A): R = (5 - 2) / 0.020 = 150 Ohms (standard E24 value).
What is the 3dB cutoff frequency of a Low Pass RC filter?
Cutoff frequency f_c = 1 / (2π × R × C). At this frequency, output voltage drops to 70.7% (1/√2) of input voltage (-3dB power attenuation).
How does a voltage divider work?
A voltage divider uses two series resistors R1 and R2 to scale down input voltage: V_out = V_in × [R2 / (R1 + R2)]. Used for analog sensor interfacing and reference voltages.