Helical resonator filter calculator
Helical resonator filter calculator — a two-section bandpass filter worked out from the passband to every dimension of the shield and helix. For VHF and UHF.
AWG to millimetres converter
AWG to mm converter — wire gauge to diameter in millimetres, cross-section in mm² and resistance, and back from mm to AWG.
Coil resistance calculator
Winding resistance from turns and wire diameter: at DC with temperature correction and at radio frequency with the skin effect. Skin depth, Q and heating.
Coil self-capacitance calculator
Coil self-capacitance calculator — find C₀ and the true inductance by regression over a series of resonances measured with different capacitors.
SMD and capacitor marking calculator
SMD code calculator — decode resistor markings (3-digit, 4-digit, R notation, EIA-96) and capacitor codes, both ways: code to value and value to code.
Air variable capacitor calculator
Air variable capacitor calculator — capacitance from plate geometry, breakdown voltage from the gap, and a reverse fit for the capacitance and voltage you need.