Electronics & RF calculators
Choose a task below. Check each calculator’s assumptions and units before using its result.
Free Stepped-Impedance Transformer Calculator
Synthesize multi-section Binomial (maximally flat) and Chebyshev (equal ripple) quarter-wave transformers for wideband RF transmission line matching.
Free Stepper Motor Heat Dissipation Calculator
Calculate winding Joule heating (I²R), core eddy current losses, surface temperature rise, and driver current limits for NEMA stepper motors.
Free Sump Pump Battery Backup Runtime Calculator
Calculate real-world battery runtime (hours and days) during torrential power outages based on pump duty cycle, motor current, and battery chemistry.
Free Supercapacitor Backup & Holdup Time Calculator
Size electric double-layer capacitor (EDLC) banks for power-loss holdup time, accounting for constant-power converter draw, ESR drop, series cell balancing, and recharge time.
Free T-Pad Attenuator Calculator
Calculate series and shunt resistor values (R1, R2, R3), power dissipation, and standard 1% resistor selections for T-network attenuators.
Free Toroid Inductor Winding Calculator
Calculate required wire turns, single-layer fit check, wire length, and DC copper resistance for iron powder and ferrite toroid cores.
Free Transformer Turns Ratio Calculator
Calculate primary-to-secondary turns ratio, step-up/step-down voltage conversion, current ratios, and reflected impedance matching.
Free Transistor Base Resistor Saturation Calculator
Calculate exact base resistor (Rb) values, forced beta overdrive, power dissipation, and GPIO safety for BJT saturation switches.
Free Twin-T Active Notch Filter Calculator
Eliminate 50Hz / 60Hz powerline hum interference in analog audio and bio-potential signals. Size R and C networks, configure active op-amp $Q$-boosting, and calculate notch depth.
Free Wilkinson Power Divider Calculator
Calculate equal and unequal Wilkinson power splitters, quarter-wave branch impedances ($Z_{02}, Z_{03}$), isolation resistor $R_{iso}$, and microstrip trace geometry.
Free Yagi-Uda Antenna Element Spacing & Gain Calculator
Design high-performance VHF/UHF Yagi antennas using DL6WU optimization rules: calculate element lengths, boom spacings, forward gain (dBi), F/B ratio, and metallic boom corrections.
Generator Step Load Calculator - Voltage Dip Sizing
Compute transient voltage sag, engine frequency drop, and recovery time during sudden block step-load applications per ISO 8528-5 and NFPA 110.
Generator Wattage Calculator - Running & Starting Watts
Size emergency standby and portable generators by calculating total running watts and motor surge starting watts with safety margins.
Hall Effect Sensor Magnetic Flux Threshold Calculator
Model cylindrical magnet axial magnetic field ($B$ in Gauss & mT), calculate digital Hall switch activation & release gap distances ($B_{op}/B_{rp}$), and size open-drain pull-up resistors.
Harmonic Distortion THD Calculator - IEEE 519 Sizing
Calculate Voltage THD (THDv), Current THD (THDi), and Total Demand Distortion (TDD) to verify compliance with IEEE 519 harmonic distortion standards.
Hartley & Colpitts LC Oscillator Frequency Calculator
Calculate resonant frequency, tank impedance, feedback ratio, and minimum sustaining voltage gain (Av) for Colpitts and Hartley LC oscillators.
High-Side P-Channel MOSFET Switch Circuit Calculator
Size BJT/N-FET level shifter resistors, gate pull-ups, and Zener clamp protection to safely drive high-side P-channel load switches from 3.3V / 5V microcontrollers.
ICCP Rectifier Sizing Calculator - Impressed Current DC
Size Impressed Current Cathodic Protection (ICCP) transformer rectifiers: calculate deepwell groundbed resistance using Dwight equations, total loop voltage, and DC power rating.
Inverter DC AC Ratio Calculator - Solar Clipping Sizing
Optimize Inverter Loading Ratio (ILR / DC-AC ratio) to balance morning/afternoon energy harvest against peak midday inverter AC clipping losses.
LLC Resonant Half-Bridge Converter Gain Calculator
Model First Harmonic Approximation (FHA) voltage gain curves, evaluate ZVS boundaries, and optimize resonant tank components (Lr, Cr, Lm) for high-efficiency PSUs.
LM317 Voltage & Constant Current Regulator Calculator
Calculate output voltage, constant current source set resistors, minimum load current, and thermal dissipation for LM317, LM338, and LM350.
Microstrip Branchline 90° Hybrid Coupler Calculator
Synthesize planar 4-port 3 dB quadrature hybrid couplers, calculate 50Ω and 35.35Ω branch line trace dimensions, and verify return loss and phase balance.
Microstrip Hairpin Bandpass Filter Calculator
Synthesize compact U-folded microstrip hairpin bandpass filters, compute coupled line spacing gaps, calculate external Q factors, and locate tapped 50Ω feed points.
Microstrip Meander Inductor Calculator - Grover & SRF
Synthesize compact serpentine/meander line planar inductors, account for negative mutual coupling between anti-parallel segments, and evaluate self-resonant frequencies (SRF).
Microstrip Rat-Race 180° Hybrid Ring Coupler Calculator
Synthesize 4-port 180° hybrid ring couplers with 3 dB power splits, calculate √2 · Z0 ring impedance, sum/difference phase balances, and layout dimensions.
Microstrip Ring Resonator Calculator
Extract dielectric permittivity (ε_r) and loss tangent (tanδ) from measured S21 ring resonance frequencies without open-end radiation loss errors.
Microstrip Stepped-Impedance Lowpass Filter Calculator
Synthesize compact planar microwave lowpass filters using alternating narrow high-Z inductive lines and wide low-Z capacitive pads on microwave PCB substrates.
MOSFET Gate Drive Resistor & Gate Charge Calculator
Size external gate resistors (Rg) to prevent gate driver overcurrent, eliminate parasitic ringing, and optimize turn-on and turn-off switching times.
Motor Fault Contribution Calculator - Short Circuit Current
Determine subtransient back-EMF fault currents from induction and synchronous motor groups feeding back into faulted buses per IEEE 242 and IEEE 551.
Motor FLA Calculator - 3-Phase Full Load Amps Sizing
Determine 3-phase AC motor full load current (FLA), 125% minimum wire sizing ampacity, and maximum overcurrent protection per NEC Article 430.
Motor Inrush Current Calculator - NEMA Locked Rotor Sizing
Compute motor starting inrush current (LRA), starting kVA, and line voltage drop from NEMA Code Letters A through V per NEMA MG-1 and NEC 430.7(B).
Neutral Grounding Resistor Calculator - NGR Sizing Amps
Determine resistance (Ω), continuous and short-time thermal power ratings (kW), and charging current thresholds for High (HRG) and Low Resistance Grounding (LRG).
NTC Thermistor Steinhart-Hart & Beta Calculator
Compute 3-point Steinhart-Hart coefficients, Beta parameters, ADC divider voltages, self-heating dissipation, and generate embedded C lookup tables (LUT).
Parallel RLC Resonant Tank Impedance & Q Factor Calculator
Calculate parallel LC resonant frequency, inductor ESR damping, tank dynamic impedance ($R_p$), unloaded/loaded Q factor, and 3dB bandwidth.
Parallel Transformer Load Sharing Calculator - KVA Sizing
Determine how two parallel-connected transformers divide total load based on their kVA ratings and percent impedances (%Z), and check for premature overloading.
Phased Array Antenna Beam Steering Phase Shift Calculator
Calculate progressive phase shift ($\Delta \phi = -\frac{2\pi d}{\lambda} \sin\theta_0$), 3dB beamwidth, grating lobe avoidance, and array factor for radar and 5G beamforming.
Piezo Buzzer Resonant Drive & Inductor Boost Calculator
Size parallel resonant boost inductors ($L = 1/(\omega_0^2 C_0)$) to amplify 3.3V/5V microcontroller outputs to 30V+ peak-to-peak without external boost converters.
Piezoelectric Cantilever Energy Harvester Calculator
Tune cantilever beam resonant frequencies to match ambient machine vibration, size tip proof masses, and calculate peak rectified DC power extraction for autonomous IoT nodes.
Power Factor Capacitor Calculator - KVAR Bank Sizing
Determine capacitor bank kVAR ratings required to raise system power factor to target levels, reduce feeder line currents, and eliminate utility penalties.
PT100 & PT1000 RTD Callendar-Van Dusen Calculator
Solve standard IEC 60751 platinum RTD resistance curves, quantify 2-wire lead resistance offsets, compare 3-wire and 4-wire bridge compensation, and limit self-heating error.
Quarter-Wave Shorted Stub DC-Ground & Lightning Surge
Calculate quarter-wave shorted stub length, RF passband insertion loss, operational bandwidth, and DC lightning surge current grounding for high-power antenna feeds.
Quarter-Wave Transmission Line Impedance Matching Calculator
Calculate characteristic impedance (Zmatch), physical cut length, velocity factor correction, and operating bandwidth for λ/4 impedance matching lines.
Quarter-Wave Transmission Line Transformer Calculator
Calculate the required characteristic impedance (Z0) and exact physical cutting length for quarter-wave (λ/4) RF impedance matching sections.
Quartz Crystal Oscillator Load Capacitance & Pierce Margin
Calculate quartz crystal load capacitors ($C_{L1}, C_{L2}$), Pierce oscillator negative resistance ($|-R|$), oscillation safety margin ($SF \ge 5$), and drive level.
RF Circulator & Isolator Power Dissipation Calculator
Size termination dump loads ($P_{dump} = P_{fwd} \cdot |\Gamma|^2$), calculate forward insertion loss, reverse isolation, and protect high-power RF transmitters from antenna mismatches.
RF Link Budget & Friis Free Space Path Loss Calculator
Calculate Free Space Path Loss (FSPL), received RF power ($P_{rx}$), receiver thermal noise floor, and fade margin (dB) for wireless IoT, cellular, and satellite links.
RF Mixer Intermodulation Spurs & IMD Table Calculator
Map all $(m \cdot f_{RF} \pm n \cdot f_{LO})$ intermodulation products up to 5th order. Identify critical in-band IF spurious responses and compare high-side vs low-side LO injection.
RF Return Loss Bridge & Reflection Coefficient Calculator
Calculate RF Wheatstone return loss bridge balance, complex reflection coefficient ($\Gamma$), return loss (dB), VSWR, and directivity measurement limits.