Voltage Divider & LC Resonance Calculator

Design DC resistor dividers, include load effects and reverse solving, and calculate LC resonance, reactances, Q, and bandwidth with SI-prefix inputs, E-series rounding, and shareable CSV exports.

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Divider

Educational estimates only. Verify with datasheets, safety standards, and full simulations before committing to hardware.

Choose the right mode first

This page combines four related electronics jobs in one place. Start by deciding whether you need a divider voltage, a loaded divider check, a reverse solve for resistor values, or LC resonance metrics.

Use the divider tabs for resistor networks

Open Divider when the output is effectively unloaded. Switch to Loaded as soon as the output feeds another resistor or circuit input, because the parallel load changes the result.

Use the LC tab for frequency work

Open LC when you need resonance frequency, reactance, Q, or bandwidth. Check the SI prefix on L and C first, then compare the reported values with your datasheet or simulation assumptions.

Before you move to hardware

Next steps

FAQ

How do I account for load when using a voltage divider?

Use the Loaded tab to add the load resistor. The calculator models the R2 ‖ RL equivalent, shows the loaded output voltage, and lets you solve for an R2 value that meets a target voltage.

Is this calculator suitable for safety-critical or production designs?

No. Treat every result as a first-order approximation. Always validate with manufacturer data, EMC and safety requirements, and, if necessary, SPICE or lab measurements before finalising a design.

Which tab should I open first?

Open Divider for an unloaded resistor divider, Loaded when the output feeds another resistor, Reverse design when you know Vin and target Vout, and LC for resonance, reactance, Q, and bandwidth.

What inputs matter most for LC resonance?

Start with inductance and capacitance in the correct SI prefix, then add series resistance if Q and bandwidth matter. Prefix mistakes such as uH vs mH are the fastest way to get a result that looks impossible.

Can I use these results directly in a production design?

No. Treat the page as a first-pass design aid. Validate tolerances, voltage ratings, parasitics, safety rules, and lab measurements before you commit parts to hardware.

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