Dragonfly Studios Laboratory

Resistor Lab

Select colors on the chart to decode a resistor. Each column represents one color band.

Interactive Color Code

4-band 5-band

Decoded resistance 47 kΩ ±1%

Select any color in the chart to change that band. The active selection is outlined. On smaller screens, scroll the chart horizontally.

Color	1st digit	2nd digit	3rd digit	Multiplier	Tolerance

Color codes follow standard resistor conventions. Gold and silver are available as multipliers and tolerance bands, but not as significant digits. Some tolerance colors are only used on particular precision resistor types.

LED resistor calculator

Calculate the series resistance needed for a target LED current.

Supply voltage (V)

LED forward voltage (V)

Desired current (mA)

Calculated resistance 300 Ω

Gearbox Lab

Change the gear sizes and motor speed to explore mechanical advantage.

Live gear simulation

The gears rotate in opposite directions. Their pitch diameters and rotational speeds follow their tooth counts.

Gear parameters

Driver teeth

Driven teeth

Gear module (mm)

Input speed (RPM)

Input torque (N·m)

Pitch diameter · driver 48 mm Pitch diameter · driven 72 mm Gear ratio · driven / driver 1.5 : 1 reduction Output speed 20 RPM Ideal output torque 0.3 N·m

Power Wheel

Rotate the wheel or select a formula to solve for voltage, current, resistance, or power.

Ohm's law + Joule's law

Select a sector, or drag the wheel to rotate it. Release to select the formula aligned with the pointer.

Power · Watts

Calculate power

P = V × I

Power Enter values below

Enter the two known values to calculate the selected variable.

Circuit Bench

This resource is planned for a future update.

Design Bench

This resource is planned for a future update.

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