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- Resistor Color Code CalculatorPick the bands to read a resistor's value and tolerance, or enter a value to see its bands
- Ohm's Law CalculatorEnter any two of voltage, current, resistance and power to get the other two
- Series & Parallel Resistor CalculatorTotal resistance of resistors in series or parallel, and the best standard pair for a target value
- Voltage Divider CalculatorOutput voltage from two resistors, or the resistor pair that gives the voltage you want
- LED Resistor CalculatorSeries resistor value and wattage for an LED from supply voltage, forward voltage and current
- RC Time Constant & Filter Cutoff CalculatorTime constant, charge time and low-pass or high-pass cutoff frequency from R and C, plus reactance and LC resonance
- Decibel Calculator (dB, dBm, Watts)Convert power and voltage ratios to dB, dBm to watts, and add decibel levels
- Drill Size Chart & Tap Drill ChartNumber, letter, fractional and metric drill sizes in inches and mm, with tap drill sizes for common threads
- Sheet Metal Gauge ChartGauge number to thickness in inches and mm for steel, galvanized, stainless and aluminum
- Scale CalculatorConvert between real size and drawing, map or model size at any scale, or find the scale from two lengths
- Gear Ratio CalculatorGear ratio, output speed and torque multiplication from tooth counts, plus spur gear dimensions from module
- Pulley & Belt Length CalculatorSpeed ratio, belt length, centre distance and belt speed from pulley diameters
- Speeds and Feeds CalculatorSpindle RPM from cutting speed and diameter, and feed rate from feed per tooth, for milling, turning and drilling
- Battery Life CalculatorEstimate how long a battery lasts from its capacity and the current your device draws
- 555 Timer CalculatorFrequency, duty cycle and pulse width for astable and monostable 555 timer circuits
- Flow Rate & Pipe Velocity CalculatorFlow from pipe size and velocity, velocity from flow and size, or the diameter you need
- Sheet Metal Bend Allowance CalculatorBend allowance, bend deduction and flat length from angle, inside radius, thickness and K-factor
- O-Ring Size ChartLook up O-ring sizes by inside diameter and cross-section (AS568, JIS B 2401, ISO 3601)
- Bearing Size ChartBore, outside diameter and width of deep-groove ball bearings by number, and how to read a bearing number
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