Calculators

Electronics calculators

Each one updates as you type and runs in your browser. The formulas are the ones the lessons are checked against, and every page links down to the lessons that explain the answer.

• Resistor colour code calculator

  Bands to ohms and ohms to bands, with the tolerance range and the nearest standard value.

  Background: The resistor colour code

• LED resistor calculator

  One LED or a string: exact and standard resistor, real current, resistor wattage.

  Background: LED circuits

• Voltage divider calculator

  Loaded and unloaded output, tolerance spread, and the best standard pair for a target.

  Background: The voltage divider

• Capacitor code calculator

  Printed code to pF, nF and µF with tolerance and voltage, and a value back to its code.

  Background: Capacitor markings

• SMD resistor code calculator

  Three-digit, four-digit, R and EIA-96 codes both ways, with checks on what you typed.

  Background: SMD resistor codes

• LM317 calculator

  R1 and R2 both ways, headroom, dissipation, heatsink, and the one-resistor current source.

  Background: Linear regulators

• Inverter battery backup calculator

  Backup hours for a home inverter, or the battery size a target time needs.

  Background: Battery types

Looking for the AI tools, such as Datasheet Guru? They live under tools. Author of the calculators: Bulan Sarkar. Found a wrong number? Tell us.