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Electronics Calculator Dashboard

Complete engineering suite for electronics: Resistor codes, Ohm's law, RC/RL circuits, Op-Amps, 555 Timers, and BJT biasing.

Resistor Code Ohm's Law RC/RL Circuit Voltage Divider LED Resistor Capacitor Inductor/Trafo BJT Bias Op-Amp All-in-One 555 Timer

Calculator 01

Resistor Color Code

R = (D1×10 + D2) × 10^Mult [4-band] | (D1×100 + D2×10 + D3) × 10^Mult [5-band]

Bands4-Band5-Band

Band 1 (1st Digit)Black – 0Brown – 1Red – 2Orange – 3Yellow – 4Green – 5Blue – 6Violet – 7Grey – 8White – 9

Band 2 (2nd Digit)Black – 0Brown – 1Red – 2Orange – 3Yellow – 4Green – 5Blue – 6Violet – 7Grey – 8White – 9

Band 3 (3rd Digit)Black – 0Brown – 1Red – 2Orange – 3Yellow – 4Green – 5Blue – 6Violet – 7Grey – 8White – 9

Band 3 (Multiplier)Black – ×1Brown – ×10Red – ×100Orange – ×1kYellow – ×10kGreen – ×100kBlue – ×1MGold – ×0.1Silver – ×0.01

ToleranceBrown – ±1%Red – ±2%Green – ±0.5%Blue – ±0.25%Violet – ±0.1%Gold – ±5%Silver – ±10%None – ±20%

Calculation Results

Resistance

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Tolerance

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Min Value

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Max Value

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Calculator 02

Ohm's Law (AC / DC)

V=IR | P=VI=I²R=V²/R | Z=√(R²+X²) | PF=cosφ=R/Z

Voltage V V

Current I A

Resistance R Ω

Power P W

Reactance X Ω (AC only)

Frequency Hz (AC only)

Calculation Results

Voltage (V)

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Current (A)

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Resistance (Ω)

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Power (W)

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Impedance Z (Ω)

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Phase Angle φ

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Power Factor

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Calculator 03

RC / RL / LC Circuit

τ=RC | τ=L/R | f₀=1/(2π√LC) | Xc=1/(2πfC) | Xl=2πfL

Circuit TypeRC CircuitRL CircuitLC ResonantRLC Series

Frequency Hz

Resistance R Ω

Capacitance C μF

Inductance L mH

Supply Voltage V

Calculation Results

Xc (Ω)

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Xl (Ω)

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Impedance Z (Ω)

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Phase Angle φ

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Time Const. τ

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Resonant Freq.

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Q Factor

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Current (A)

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Calculator 04

Voltage Divider

Vout = Vin × R2/(R1+R2) | With load: Vout = Vin × (R2||RL) / (R1 + R2||RL)

Input Voltage Vin V

R1 Ω

R2 Ω

Load RL Ω (optional)

Desired Vout V (find R2)

ModeCalculate VoutFind R2 for target Vout

Calculation Results

Vout (no load)

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Vout (with load)

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Current (mA)

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Power in R1+R2 (mW)

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Loading Error %

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R2 for target Vout

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Calculator 05

LED Current Limiting Resistor

R = (Vs − N×Vf) / If | P_R = If² × R | P_LED = N × Vf × If

Supply Voltage Vs V

LED Forward Voltage Vf V

LED Forward Current If mA

No. of LEDs in Series

LED Color / TypeRed (1.8–2.2V)Orange (2.0–2.2V)Yellow (2.1–2.4V)Green (3.0–3.5V)Blue (3.2–3.6V)White (3.0–3.5V)IR (1.5–1.9V)Custom

No. of Parallel Strings

Calculation Results

Resistor Value

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Nearest E24

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Power in R (mW)

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Total LED Power

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Calculator 06

Capacitor Charge & Energy

Q = C×V | E = ½CV² | Vt = V₀(1−e^−t/RC) | ΔVripple = I/(f×C)

Capacitance C μF

Voltage V V

Resistance R Ω

Time t ms

Load Current mA (ripple)

Frequency Hz (ripple)

Calculation Results

Charge Q (μC)

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Energy E (mJ)

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Voltage at t

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Ripple Voltage

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Time Const. τ (ms)

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63% Charge Time

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99% Charge Time

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Calculator 07

Inductor & Transformer

Xl = 2πfL | EMF = N×dΦ/dt | N1/N2 = V1/V2 = I2/I1 | L = μ₀μ_rN²A/l

Inductance L mH

Frequency Hz

Primary Voltage V1 V

Secondary Voltage V2 V

Primary Turns N1

Load Current I2 A

Calculation Results

Xl (Ω)

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Turns Ratio N1:N2

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N2 (Secondary)

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Primary Current I1

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Apparent Power

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Reflected R (Ω)

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Efficiency (est.)

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Calculator 08

BJT Transistor Bias

Vb = Vcc×R2/(R1+R2) | Ve = Vb−Vbe | Ie≈Ic = Ve/Re | Vc = Vcc−Ic×Rc

Vcc Supply V

β (hFE) — Current Gain

R1 Ω

R2 Ω

Rc — Collector Ω

Re — Emitter Ω

Calculation Results

Vb (Base)

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Ve (Emitter)

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Vc (Collector)

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Vce (Q-point)

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Ic (mA)

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Ib (μA)

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Region

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Stability S

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Calculator 09

Op-Amp Gain Calculator

Inv: Gain = −Rf/Rin | Non-Inv: 1+Rf/R1 | Diff: Vout=(V2−V1)×Rf/R1

Amplifier TypeInvertingNon-InvertingDifferentialSumming (2 inputs)

Rin / R1 kΩ

Rf — Feedback kΩ

Vin1 V

Vin2 V (diff/sum only)

Supply Voltage ±Vcc V

Calculation Results

Gain (dB)

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Gain (V/V)

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Vout

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Clipping?

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Calculator 10

Electronics All-in-One Summary

Full circuit analysis: V, I, R, P → RC time constant → Divider → LED resistor → Power budget

Supply Voltage V

Total Load Ω

Capacitance μF

Inductance mH

Frequency Hz

LED Vf V

LED If mA

No. LEDs (series)

Calculation Results

Current (mA)

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Power (mW)

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Xc (Ω)

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Xl (Ω)

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Impedance Z (Ω)

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RC Time Const.

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RL Time Const.

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Resonant Freq.

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LED Resistor

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Total Power

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Calculator 11

555 Timer Calculator

Astable: T_high = 0.693(R1+R2)C | T_low = 0.693(R2)C | Monostable: T = 1.1RC

ModeAstable (Oscillator)Monostable (One-Shot)

Capacitance C μF

Resistance R1 kΩ

Resistance R2 kΩ

Calculation Results

Frequency

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High Time (T_high)

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Low Time (T_low)

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Duty Cycle

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Data Management

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