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Found 227 calculators
Electric charge from current and time
Calculates electric charge from current and time.
Current from charge and time
Calculates current from electric charge and time.
Time from charge and current
Calculates time from electric charge and current.
Conductance from resistance
Calculates conductance as the reciprocal of resistance.
Resistance from conductance
Calculates resistance as the reciprocal of conductance.
LED resistor calculator
Calculates resistance and resistor power for an LED current limiting resistor.
LED series resistor
Calculates a current limiting resistor for multiple LEDs connected in series.
LED resistor power
Calculates power dissipated in an LED current limiting resistor.
Zener resistor
Calculates the series resistor for a simple Zener diode regulator.
BJT base resistor
Calculates a base resistor for simplified BJT transistor drive.
Bridge rectifier average output
Estimates average voltage of an unloaded full-wave waveform without a smoothing capacitor.
Rectifier smoothing capacitor
Calculates ripple for a selected capacitance or required capacitance for an allowed ripple.
Diode conduction power loss
Calculates diode power loss from constant forward voltage and average current or conduction current with duty cycle.
BJT voltage divider bias
Calculates a simplified BJT operating point from base divider, emitter resistor and collector resistor.
MOSFET external gate resistor
Estimates required external gate resistance from gate charge and switching time.
MOSFET conduction loss
Calculates conduction loss from RMS current, Rds(on) and duty cycle.
MOSFET switching loss
Estimates MOSFET dynamic losses from voltage, current, switching times, frequency and gate-drive power.
Semiconductor junction temperature
Calculates junction temperature from ambient or case temperature with known power loss and thermal resistance.
Inverting op-amp gain
Calculates voltage gain of an ideal inverting operational amplifier.
Non-inverting op-amp gain
Calculates voltage gain of an ideal non-inverting operational amplifier.
RC low-pass cutoff
Calculates cutoff frequency of a simple RC low-pass filter.
RC high-pass cutoff
Calculates cutoff frequency of a simple RC high-pass filter.
PWM average voltage
Calculates PWM average voltage for duty cycle in the 0..1 range.
ADC resolution
Calculates ADC voltage step from reference voltage and bit count.
ADC code from voltage
Calculates ideal ADC code from input voltage, reference voltage and bit count.
Resistor voltage divider
Calculates output voltage of an ideal two-resistor divider.
Loaded voltage divider
Calculates output voltage of a resistor divider with load resistance in parallel with the lower resistor.
Current divider for two resistors
Calculates branch currents in an ideal two-resistor current divider.
Op-amp inverting gain
Calculates gain and output voltage of an ideal inverting op-amp.
Op-amp non-inverting gain
Calculates gain and output voltage of an ideal non-inverting op-amp.
Three-input op-amp summing amplifier
Calculates output voltage of an ideal inverting summing amplifier with three input resistors.
Matched-ratio op-amp differential amplifier
Calculates differential amplifier output for matched resistor ratios.
Op-amp integrator for constant input
Calculates output change and final voltage of an ideal integrator for a constant input voltage.
Op-amp differentiator for linear ramp
Calculates ideal op-amp differentiator output for a constant input voltage slope.
Op-amp maximum frequency from slew rate
Estimates maximum sine frequency from slew rate and peak output voltage.
Op-amp closed-loop bandwidth
Estimates closed-loop bandwidth from gain-bandwidth product and gain magnitude.
Duty cycle from on-time
Calculates PWM duty cycle and frequency from on-time and period.
Resistor power dissipation
Calculates power dissipated in a resistor from voltage and resistance.
Basic RL time constant
Calculates the time constant of a simple RL circuit from inductance and resistance.
PCB trace resistance
Calculates resistance of a simple PCB trace from resistivity, length, width and copper thickness.
PCB trace width and current
Estimates required width or approximate current of a PCB trace with an older simplified empirical model.
Logic gate
Calculates the output of a NOT, AND, OR, NAND, NOR, XOR, or XNOR gate for boolean/0/1 values.
Truth table up to 3 inputs
Generates a truth table for the selected gate and 1-3 inputs without an expression parser.
First-order RC filter
Solves f_c = 1/(2*pi*R*C) for a simple first-order RC filter.
1st-order crossover LP: series inductor
Sizes the series inductor for a first-order low-pass speaker crossover with resistive load R.
1st-order crossover HP: series capacitor
Sizes the series capacitor for a first-order high-pass speaker crossover with resistive load R.
2nd-order Butterworth low-pass crossover
Sizes the ideal LP topology: series inductor and shunt capacitor terminated by R.
2nd-order Butterworth high-pass crossover
Sizes the dual HP topology: series capacitor and shunt inductor terminated by R.
RC cutoff frequency
Calculates cutoff frequency of a simple RC filter.
RL cutoff frequency
Calculates cutoff frequency of a simple RL filter.
RL low-pass cutoff
Calculates cutoff frequency of a simple ideal RL low-pass filter.
LC resonant frequency
Calculates resonant frequency of an ideal LC circuit.
Ohm's law voltage
Calculates voltage from current and resistance in a DC circuit.
Ohm's law current
Calculates current from voltage and resistance in a DC circuit.
Ohm's law resistance
Calculates resistance from voltage and current in a DC circuit.
DC electrical power
Calculates DC electrical power from voltage and current.
DC power from current and resistance
Calculates DC power from current and resistance.
DC power from voltage and resistance
Calculates DC power from voltage and resistance.
Electrical demand power
Calculates demand power from total installed active power and a manually supplied demand factor. Energy demand in kWh additionally requires operating time and is a separate calculation.
Single-phase power
Calculates single-phase active power from voltage, current and power factor.
Reactive power from S and P
Calculates reactive power from apparent and active power.
Power factor from kW and kVA
Calculates power factor as active power divided by apparent power.
Electrical energy consumption estimate
Estimates daily and annual site electricity consumption from installed power, average utilization, operating hours per day, and operating days per year.
Electrical energy from power and time
Calculates electrical energy from power and operating time.
Energy cost
Calculates energy cost from energy amount and price per kWh.
Joule heating
Calculates energy dissipated in resistance from current and time.
Resistors in series
Calculates the total resistance of resistors connected in series.
Resistors in parallel
Calculates the total resistance of resistors connected in parallel.
Wire resistance
Calculates theoretical wire resistance from resistivity, length and cross-sectional area.
Resistance temperature coefficient
Calculates resistance after a temperature change using a linear temperature coefficient.
Conductivity from resistivity
Calculates electrical conductivity as the reciprocal of resistivity.
Resistor current limit from power
Calculates maximum current from resistor power rating and resistance.
Resistor voltage limit from power
Calculates maximum voltage from resistor power rating and resistance.
Preferred E-series resistor
Selects the nearest E12, E24, E48 or E96 resistor value.
Resistor color code
Decodes 4-, 5- and 6-band resistors.
Rectifier and ripple
Estimates rectifier voltage and ripple with a filter capacitor.
Voltage divider
Calculates the output voltage of an ideal resistor divider.
RC time constant
Calculates the time constant of a simple resistor-capacitor circuit.
DC current divider for two branches
Calculates currents in two parallel resistive branches of an ideal current divider.
Unknown branch current from KCL
Calculates signed unknown branch current from current balance; a negative result means the opposite direction to the assumption.
Unknown voltage from KVL
Calculates signed unknown voltage from a loop balance using the supplied source/drop convention.
DC source loaded voltage
Calculates DC source terminal voltage from source voltage, current, and internal resistance.
DC source internal power loss
Calculates power loss in a source internal resistance from current and resistance.
Power ratio and dB
Converts a positive power ratio and decibels.
Voltage ratio and dB
Converts voltage ratio to dB for equal impedances.
dBm and dBW power levels
Converts watts and dBm/dBW power levels.
dBm and dBW converter
Converts dBm and dBW power levels.
555 astable timer
Calculates ideal 555 astable oscillator parameters.
555 monostable timer
Calculates the pulse time of an ideal 555 monostable circuit.
Complex number: rectangular to polar
Converts real and imaginary parts to magnitude and phase.
Complex number: polar to rectangular
Converts magnitude and phase to real and imaginary parts.
Two complex impedances in series
Adds two impedances written as R + jX and returns real part, imaginary part, magnitude, and phase.
Two complex impedances in parallel
Combines two impedances written as R + jX in parallel and reports a zero-denominator error.
Period from frequency
Calculates waveform period from frequency.
Angular frequency
Calculates angular frequency from frequency.
RMS from peak
Calculates sinusoidal RMS voltage from peak voltage.
Peak from RMS
Calculates sinusoidal peak voltage from RMS voltage.
Capacitive reactance
Calculates capacitor reactance magnitude at a given frequency.
Inductive reactance
Calculates inductor reactance at a given frequency.
RC impedance magnitude
Calculates impedance magnitude of a series RC model.
RL impedance magnitude
Calculates impedance magnitude of a series RL model.
Series RLC impedance magnitude
Calculates impedance magnitude of a series RLC model.
Series RLC bandwidth and quality
Calculates resonant angular frequency and frequency, bandwidth, Q factor, and damping ratio.
Series RLC half-power frequencies
Calculates lower and upper half-power frequencies and bandwidth of an ideal series RLC circuit.
Series RLC quality factor
Calculates Q factor of an ideal series RLC circuit from inductance, capacitance and resistance.
LC resonant frequency
Calculates resonant frequency of an ideal LC circuit.
Parallel RLC branch currents
Calculates R, L, and C branch currents, reactive component, total current, phase, and power factor.
Power factor from phase angle
Calculates power factor as cosine of phase angle.
Single-phase apparent power
Calculates single-phase apparent power from RMS voltage and RMS current.
Single-phase active power
Calculates single-phase active power from RMS voltage, RMS current and power factor.
Single-phase reactive power
Calculates single-phase reactive power from RMS voltage, RMS current and phase angle.
Parallel RLC circuit
Calculates admittance, impedance, branch currents and resonance of a simple parallel RLC circuit.
Wheatstone bridge
Calculates bridge output voltage and an unknown resistance at balance.
Capacitor energy
Calculates stored capacitor energy from capacitance and voltage.
Capacitor charge
Calculates capacitor charge from capacitance and voltage.
Capacitor voltage from charge
Calculates capacitor voltage from charge and capacitance.
Parallel-plate capacitor
Calculates ideal parallel-plate capacitance from geometry and relative permittivity.
Capacitors in parallel
Calculates equivalent capacitance for capacitors connected in parallel.
Capacitors in series
Calculates equivalent capacitance for capacitors connected in series.
RC charging capacitor voltage
Calculates capacitor voltage during charging of an ideal RC circuit.
RC discharging capacitor voltage
Calculates capacitor voltage during discharge of an ideal RC circuit.
RC charging time to voltage
Calculates the time for a capacitor in an ideal RC circuit to reach a target voltage.
Inductor energy
Calculates stored energy in an ideal inductor from inductance and current.
RL time constant
Calculates the time constant of a simple resistor-inductor circuit.
Inductors in series
Calculates equivalent inductance for inductors connected in series.
Inductors in parallel
Calculates equivalent inductance for inductors connected in parallel.
Inductor voltage from current slope
Calculates voltage across an ideal inductor from inductance and current slope.
Long straight wire magnetic field
Calculates magnetic flux density around a long straight wire from current, distance and μr.
Circular loop center magnetic field
Calculates magnetic flux density at the center of an N-turn circular loop.
Ideal solenoid magnetic field
Calculates H, B and turn density for a long ideal solenoid.
Simple magnetic circuit
Calculates reluctance, MMF, flux and B/H for one core segment with an optional air gap.
Magnetic field energy density
Calculates linear magnetic field energy density from B and constant relative permeability μr.
Air-gap electromagnet force
Calculates ideal electromagnet force in a uniform gap from supplied B or from N, I and g.
RF wavelength
Calculates wavelength from frequency and velocity factor.
Antenna length from wavelength fraction
Calculates 1/4, 1/2 or 5/8 wavelength length from frequency and VF.
Free-space path loss
Calculates wavelength and FSPL in linear scale and dB for a supplied propagation speed.
RF link budget
Sums transmitter power, gains and losses in dB/dBm and calculates link margin.
Friis received power
Calculates received power from transmitted power, linear gains, wavelength and distance.
EIRP
Calculates equivalent isotropic radiated power in dBm from transmitter power, antenna gain and feeder loss.
Antenna effective aperture
Calculates antenna effective aperture from linear gain and wavelength.
Conductor skin depth
Calculates skin depth from frequency, resistivity and relative magnetic permeability.
Coaxial line impedance
Calculates impedance of a homogeneous non-magnetic coaxial line from geometry and dielectric permittivity.
Quarter-wave transformer
Calculates quarter-wave section impedance for real positive source and load impedances.
Simple microstrip impedance
Estimates microstrip impedance from trace width, substrate height and relative permittivity.
Reflection coefficient Γ
Calculates complex reflection coefficient from ZL and Z0 or from short/open-circuit cases.
VSWR from |Γ|
Calculates voltage standing wave ratio for |Γ| ≤ 1.
Return loss from |Γ|
Calculates return loss; for Γ = 0 it returns a structured +∞ dB result.
Mismatch loss from |Γ|
Calculates mismatch loss for |Γ| ≤ 1.
RF power balance
Calculates reflected and delivered power from incident power and |Γ|.
Rectangular waveguide TE10 cutoff
Calculates TE10 cutoff frequency and, above cutoff, guided wavelength.
Transmission-line electrical length
Calculates β and electrical length from physical length, frequency and VF.
Transformer secondary voltage
Calculates ideal transformer secondary voltage from turns ratio.
Transformer secondary voltage helper
Helper calculation for ideal transformer secondary voltage from primary voltage and turn counts.
Transformer secondary current
Calculates ideal transformer secondary current from turns ratio.
Transformer turns ratio
Calculates secondary-to-primary turns ratio.
Transformer efficiency
Calculates transformer efficiency from output and input power.
Transformer apparent power
Calculates primary and secondary apparent power from voltage and current.
Transformer copper loss
Calculates primary and secondary I²R winding losses from currents and resistances.
Transformer voltage regulation
Calculates voltage regulation as a fraction with percent display support.
Transformer efficiency from losses
Calculates efficiency from output power plus core, copper and additional losses.
Reflected transformer impedance
Calculates impedance reflected to the primary side of an ideal transformer.
Transformer secondary current from apparent power
Calculates ideal transformer secondary current from apparent power and secondary voltage.
Synchronous speed
Calculates motor synchronous speed from frequency and pole count.
Motor slip
Calculates slip from synchronous speed and rotor speed.
Motor slip percent
Helper calculation for percent slip from synchronous speed and rotor speed.
Motor torque from power and speed
Calculates approximate torque from power in kW and rotational speed.
Motor power from torque and speed
Calculates approximate power from torque and rotational speed.
Motor efficiency
Calculates motor efficiency as output power divided by input power.
Motor input power
Calculates input power from output power and efficiency.
DC motor back EMF
Calculates back EMF from supply voltage, armature current and armature resistance; with a back-EMF constant it also gives angular speed.
DC motor starting current and torque
Calculates current and torque at zero back EMF in a simple armature model.
Simple three-phase motor current
Calculates approximate three-phase motor current from power, voltage, power factor, and efficiency.
Battery energy in Wh
Estimates battery energy from nominal voltage and amp-hour capacity.
Battery runtime
Estimates runtime from battery capacity and load current.
Battery runtime with efficiency
Estimates runtime from capacity, system efficiency and load current.
Current from C-rate
Estimates current from C-rate and battery capacity.
Battery charge time
Roughly estimates charge time from capacity and charge current.
Series battery pack voltage
Calculates pack voltage from series cell count and cell voltage.
Parallel battery pack capacity
Calculates pack capacity from parallel cell count and single-cell capacity.
Battery voltage sag
Calculates approximate voltage drop across internal resistance at a given current.
Three-phase apparent power
Calculates theoretical apparent power of a balanced three-phase system.
Three-phase active power
Calculates theoretical active power of a balanced three-phase system.
Three-phase reactive power
Calculates theoretical reactive power from phase angle for a three-phase system.
Three-phase current from active power
Calculates theoretical line current from active power, line voltage and power factor.
Star phase voltage
Calculates theoretical phase voltage from line voltage in a star connection.
Delta phase current
Calculates theoretical phase current from line current in a delta connection.
Theoretical power factor correction
Calculates simplified theoretical correction power for improving power factor.
Power factor correction capacitor
Helper calculation for correction capacitance from active power and power-factor change; it is not a standards-based installation design.
Three-phase power from line voltage
Calculates active power of a balanced three-phase system from line-line voltage.
Theoretical DC voltage drop
Calculates approximate voltage drop for a simple DC circuit with outgoing and return conductors.
Voltage drop percent
Converts voltage drop to a percentage of nominal voltage.
Theoretical three-phase voltage drop
Calculates simplified voltage drop in a balanced three-phase system from per-length parameters.
Cable current density
Calculates current density as current divided by cross-sectional area.
Cable resistance from resistivity
Calculates resistance of a uniform conductor from resistivity, length, and cross-sectional area.
DC two-wire voltage drop
Helper calculation for DC voltage drop from current, resistance per meter and length; it is not standards-based conductor sizing.
Single-phase voltage drop
Helper calculation for simplified single-phase voltage drop from resistivity and area; it is not standards-based conductor sizing.
Three-phase voltage drop from resistivity
Helper calculation for simplified three-phase voltage drop from resistivity and area; it does not replace standards-based calculations.
Cable power loss
Helper calculation for cable power loss from current and resistance; it is not an allowable-load assessment.
AWG wire resistance and mass
Calculates AWG geometry, resistance, metal mass, and optional voltage drop and power loss.
AWG to conductor diameter and area
Calculates diameter and solid circular conductor area for AWG sizes from 4/0 to 40.
Cable ampacity after correction
Multiplies the manually provided base ampacity Iz by a correction factor.
Manual cable overload conditions check
Checks the provided Ib, In, Iz and I2 values without standards-table sizing.
Exact Iz lookup from user table
Looks up base ampacity Iz only for an exactly entered section in the user-supplied table.
Single-phase selection from user table
Selects the smallest entered section that meets the manual current conditions and voltage-drop limit.
Three-phase selection from user table
Selects the smallest entered section for a simplified balanced three-phase system.
Manual single-phase cable sizing check
Combines load current, manually corrected Iz, voltage drop and overload-condition checks.
Manual three-phase cable sizing check
Checks a balanced three-phase system with manually provided Iz, protective-device and voltage-drop data.
Manual WLZ check
Simplified manual WLZ check using installed power and demand factor.
Historical insulated-copper ampacity
Historical data from a 1938 publication. Exact Iz lookup for educational and comparative use only.
Historical minimum copper section
Historical data from a 1938 publication. Smallest-section selection without interpolation, for educational and comparative use only.
Historical underground three-core cable ampacity
Historical 1000 V cable data from a 1938 publication, for educational and comparative use only.
Manual Iz compared with historical value
Compares manually entered Iz with the historical insulated-copper value without PASS/FAIL judgement.
Simple fault current
Calculates approximate fault current from voltage and loop impedance.
Theoretical short-circuit power
Calculates approximate short-circuit power from voltage and impedance.
Theoretical maximum loop impedance
Calculates theoretical maximum loop impedance from voltage and trip current.
Simple protection fault-loop current
Calculates simplified current from voltage and loop impedance.
Simple fault-loop current
Helper calculation for current from voltage and loop impedance; it is not protection assessment or standards-based protective-device selection.
Simple touch voltage
Helper calculation for voltage from fault current and resistance; it is not a standards-based safety interpretation.
Theoretical touch voltage
Calculates approximate touch voltage from fault current and earth resistance.
Ground resistance from voltage and current
Calculates resistance as voltage divided by current in a simplified model.
Theoretical earth fault current
Calculates approximate earth fault current from voltage and loop impedance.
Advanced PCB designer
Interactive stack-up, trace-segment and via-group designer with resistance, voltage drop, power loss and user-defined limits.
Antenna and waveguide suite
Three-tab RF suite for rectangular waveguides, dipoles with link budget, and rectangular patch antennas with visualization and JSON export.
Cable and feeder sizing designer
Manual verification of a selected cable and feeder: Ib, corrected Iz, protective device, voltage drop and explicit margins without normative tables.
Circuit Analysis Solver
Local MNA solver for linear DC and AC circuits with RLC elements, independent and controlled sources, phasors, complex power and frequency sweeps.
RF transmission line designer
RF line design and analysis for coax, quasi-TEM microstrip, RLGC propagation, load transformation, quarter-wave matching and frequency sweep.
Speaker enclosure designer
Interactive sealed and bass-reflex enclosure designer with Thiele-Small parameters, net and gross volume, ports, impedance model, excursion, SPL, user limits, import and export.