Calculateur de LED Series Resistor
Calculate the resistor value needed to safely drive an LED from a supply voltage.
Formula and method
This calculator computes Resistor value directly in your browser without sending data to an external server.
Mathematical formula
- Resistor value:
supplyVoltage<=ledVoltage ? NaN : (supplyVoltage-ledVoltage) ÷ (ledCurrentMa ÷ 1000)
Variables and parameters
- Supply voltage (supplyVoltage): default value 5 V.
- LED forward voltage (ledVoltage): default value 2 V.
- LED forward current (ledCurrentMa): default value 20 mA.
Some formulas are undefined for certain input combinations (such as division by zero or logarithms of non-positive numbers). In those cases the live tool displays an alert instead of NaN.
Embed this tool
Paste this snippet into your own site or blog post to embed a live, working copy of this tool. It links back to the full page on SpecWhale.
Frequently asked questions
What equation and variables does LED Series Resistor Calculator use?
LED Series Resistor Calculator evaluates outputs such as <strong>Resistor value</strong> based on inputs including Supply voltage, LED forward voltage, LED forward current. Check the Mathematical Method section for the explicit formula.
What happens if I enter invalid or zero values into LED Series Resistor Calculator?
If an input combination is mathematically undefined (such as division by zero or negative square roots), SpecWhale alerts you gracefully rather than returning invalid NaN outputs.
Are my calculations in LED Series Resistor Calculator saved or private?
All calculations are 100% private and run locally in your Web browser. Your numbers are never uploaded to any server, but can be saved locally to your device or exported as CSV/JSON.
Is LED Series Resistor Calculator free to use?
Yes. LED Series Resistor Calculator is completely free, has no usage limit, and does not require an account, email, or API key.
Does LED Series Resistor Calculator store or upload my data?
No. LED Series Resistor Calculator calculates everything locally in your browser. Nothing you type is sent to a server or stored by SpecWhale.
How accurate is LED Series Resistor Calculator?
LED Series Resistor Calculator uses a standard formula (see the Method section above for the exact expression). For high-stakes financial, medical, or legal decisions, confirm the result with a professional or an authoritative source before relying on it.
Can I embed LED Series Resistor Calculator on my own website?
Yes. Use the "Embed this tool" snippet on this page to add a free, working copy of LED Series Resistor Calculator to your own blog post or page.