calculators, web tools for electronics
Ham Radio Tools SWR & Return Loss Calculator Convert between SWR, return loss, reflection coefficient, reflected power ratio, and mismatch loss. Add forward power when you want reflected watts and net power at the measurement point. SWR and reflected power diagram A transmitter sends forward power through a feedline to an antenna, with a smaller … Read more
Electronics Tools Resistor Series / Parallel Calculator Calculate the equivalent resistance of two or more resistors connected in series or parallel. Add your resistor values, choose the connection type, and optionally enter a voltage to check current and power. Resistor network diagram Clean schematic drawings showing two resistors in series and two resistors in parallel. … Read more
Electronics Tools Ohm’s Law Calculator Solve voltage, current, resistance, and power for basic DC circuits. Pick the unknown value, enter the other two values, and the calculator handles the unit conversion. Ohm’s law diagram Voltage, current, and resistance arranged around the Ohm’s law relationship. V I R V = I x R What this tool … Read more
Electronics Tools LED Resistor Calculator Choose a current limiting resistor for a single LED. Enter the supply voltage, forward voltage, and target LED current to estimate resistance, heat, and a practical standard resistor value. LED with current limiting resistor A simple DC circuit showing a supply, resistor, LED, and ground return. +Vs R LED GND … Read more
Ham Radio Tools Antenna Length Calculator Estimate starting lengths for common ham radio antennas from frequency. Calculate half-wave dipoles, quarter-wave verticals, full-wave loops, end-fed half-wave wires, 5/8-wave verticals, and custom wavelength fractions in feet and meters. Wire antenna length diagram A simple ham radio antenna diagram showing a center-fed dipole, a vertical antenna, and radio … Read more
Electronics Tools Voltage Divider Calculator Calculate a two-resistor voltage divider. Solve for output voltage, input voltage, R1, or R2, then check divider current and resistor power before using the values in a real circuit. Voltage divider schematic Two resistors in series from input voltage to ground with output taken from the middle node. Vin R1 … Read more
Electronics Tools Resistor Color Code Calculator Decode 4-band and 5-band resistor color codes into resistance and tolerance. Use it when reading through-hole resistors in Arduino, ESP32, sensor, and breadboard circuits. Resistor with color bands A through-hole resistor with live color bands and metal leads. color bands to value significant digits x multiplier, then tolerance What … Read more
Ham Radio Tools Coax Electrical Length Calculator Calculate the physical length of coax needed for a target electrical length. Enter frequency, coax velocity factor, and phase length to find quarter-wave, half-wave, full-wave, or custom cable sections for ham radio feedlines, stubs, and phasing lines. Coax cable with wavelength marks A coax cable path with quarter-wave, … Read more
Ham Radio Tools Coax Loss Calculator Estimate how much transmit power is lost in a coaxial feedline before it reaches the antenna. Enter the operating frequency, coax type, cable length, and transmitter power to calculate line loss, antenna-end power, efficiency, and heat lost in the cable. Transmitter, coax feedline, and antenna A station diagram showing … Read more