Ham Radio Electronics Calculators
Ten electronics calculators for amateur radio: Ohm's law, inductive and capacitive reactance, LC resonance, dBm conversion, decibel cascading, voltage divider, RC/RL time constants, Wheeler coil inductance, transformer turns ratio, and resistor colour code decoder.
Ohm's Law Calculator
Enter any two known values to calculate the remaining two. Covers voltage, current, resistance, and power.
Inductive and Capacitive Reactance Calculator
Calculates XL (inductive reactance) and XC (capacitive reactance) at any frequency. Also shows impedance for series and parallel LC.
LC Resonant Frequency Calculator
Resonant frequency from L and C values, or calculates the required L or C to resonate at a target frequency.
dBm, dBW and Watts Converter
Converts between dBm, dBW, watts, and milliwatts. Includes a reference table for common amateur radio power levels.
Decibel Gain / Loss Calculator
Converts between dB and power/voltage ratios, cascades multiple gain/loss stages, and shows end-to-end system gain.
Voltage Divider Calculator
Output voltage, current draw, and power dissipation for a resistive voltage divider. Also calculates required R2 for a target output voltage.
RC and RL Time Constant Calculator
Time constant tau, rise/fall times, -3dB frequency, and charge/discharge voltage at any time for RC and RL circuits.
Wheeler Single-Layer Coil Inductance Calculator
Inductance of a single-layer air-core coil using the classic Wheeler formula. Accurate to within 1% for most practical coils.
Transformer Turns Ratio and Impedance Calculator
Turns ratio from impedance ratio, or impedance ratio from turns. Also calculates secondary voltage and current from primary values.
Resistor Colour Code Decoder
Decodes 4-band and 5-band resistor colour codes to resistance value and tolerance. Also encodes a resistance value to colour bands.