LED Resistor Calculator
Find the series resistor and power rating needed to drive an LED.
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Resistor Color Code Calculator
Decode 4-band and 5-band resistor color codes with tolerance.
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Solve voltage, current, resistance and power from any two values.
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Test JavaScript regular expressions with live match highlighting.
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Encode text to Base64 or decode Base64 back to UTF-8 text.
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Pretty-print, minify and validate JSON with exact error positions.
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