EE Toolbox — Kyros Engineering

Ohm's Law

V = I × R — Enter any two values to solve for the third.

Voltage (V)V

Current (I)A

Resistance (R)Ω

Power Calculator

P = V×I | P = I²R | P = V²/R

Voltage (V)V

Current (I)A

Resistance (R)Ω

Voltage Divider

Vout = Vin × R2 / (R1 + R2)

VinV

R1 (top)Ω

R2 (bottom)Ω

Current Divider

For two parallel resistors: I1 = Itotal × R2 / (R1 + R2)

Total CurrentA

R1Ω

R2Ω

Series / Parallel Resistors

Enter resistor values separated by commas.

ResistorsΩ

Series / Parallel Capacitors

Enter capacitor values separated by commas (in the chosen unit).

Capacitors

Series / Parallel Inductors

Enter inductor values separated by commas (in the chosen unit). Assumes no mutual coupling.

Inductors

RC Time Constant

τ = R × C — with charge / discharge curve plot.

ResistanceΩ

Capacitance

Supply VoltageV

LC Resonant Frequency

f = 1 / (2π√(LC))

Inductance

Capacitance

555 Timer Calculator

Astable and monostable modes.

R1Ω

R2Ω

C

RΩ

C

RC Filter Cutoff Frequency

fc = 1 / (2πRC) — low-pass or high-pass single-pole filter.

ResistanceΩ

Capacitance

Resistor Color Code

Bidirectional: enter a value to see bands, or pick band colors to see the value.

Value → Color Bands

ResistanceΩ

Band Count

Color Bands → Value

Bands

Standard Value Finder

Find the nearest E-series standard resistor value.

Target ValueΩ

Series

LED Resistor Calculator

R = (Vsupply - Vf) / If

Supply VoltageV

LED Forward V (Vf)V

LED Current (If)mA

Capacitor Charge Energy

E = ½CV²

Capacitance

VoltageV

PCB Trace Width Calculator

IPC-2221 formula for required trace width given current.

CurrentA

Copper Weight

Temp Rise°C

Layer

Microstrip Trace Impedance

Approximate Z0 for an outer-layer microstrip trace.

Trace Width (W)mm

Dielectric Height (H)mm

Copper Thickness (T)mm

Dielectric Const (Er)

Thermal Resistance Chain

Tj = Ta + Pdiss × (Rjc + Rcs + Rsa)

Power DissipationW

Rjc (junction→case)°C/W

Rcs (case→sink)°C/W

Rsa (sink→ambient)°C/W

Ambient Temp°C

Heatsink Sizing

Required heatsink thermal resistance: Rsa = (Tj_max - Ta) / P - Rjc - Rcs

Power DissipationW

Max Junction Temp°C

Ambient Temp°C

Rjc°C/W

Rcs°C/W

dBm ↔ Watts ↔ Volts

Convert between dBm, watts, and RMS volts (with impedance).

ImpedanceΩ

dBm

PowerW

VrmsV

AWG ↔ mm² Wire Gauge

Convert between AWG and metric wire sizes. Includes diameter, area, and max current (chassis wiring).

AWG

Diametermm

Cross-sectionmm²

Frequency ↔ Period ↔ Wavelength

f = 1/T, λ = c/f

Frequency

Period

Wavelength

Temperature Converter

°C ↔ °F ↔ K

Celsius°C

Fahrenheit°F

KelvinK

Data Rate Converter

Convert between bps, kbps, Mbps, Baud, and bytes/s.

Value

Unit

Bits per Symbol(for Baud)

Voltage / Power dB Calculator

dB(power) = 10·log10(P2/P1) | dB(voltage) = 20·log10(V2/V1)

P1 (reference)W

P2W

V1 (reference)V

V2V

Free Space Path Loss

FSPL(dB) = 20·log10(d) + 20·log10(f) + 20·log10(4π/c)

Distance

Frequency

Skin Depth Calculator

δ = √(2ρ / (ωμ))

Frequency

Material

Rel. Permeability μr

VSWR ↔ Return Loss ↔ Reflection Coefficient

Enter any one value to compute the others.

VSWR

Return LossdB

|Γ| (refl. coeff.)

Mismatch LossdB

Antenna Gain Converter

dBi = dBd + 2.15

Gain (dBi)

Gain (dBd)

Linear gain

Non-Inverting Op-Amp Gain

Av = 1 + Rf/Rg

Rf (feedback)Ω

Rg (ground)Ω

Inverting Op-Amp Gain

Av = -Rf / Rin

Rf (feedback)Ω

Rin (input)Ω

Transimpedance Amplifier

Vout = -Iin × Rf — Current-to-voltage converter (photodiode front-end, etc.)

Input Current

Rf (feedback)Ω

Cf (optional, bandwidth)