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Convert mm to mil

Convert millimetres to mils instantly. 1 mm = 39.37 mil. The unit conversion you need for PCB trace width and clearance work, straight from the number you type.

Convert mil to mm

Convert mils to millimetres instantly. 1 mil = 0.0254 mm. Common PCB values such as 4 mil and 30 mil are one keystroke away.

Convert mm to inches

Convert millimetres to inches. The unit conversion used in PCB layout and mechanical design, with the result as you type.

Convert inches to mm

Convert inches to millimetres. The unit conversion used in PCB layout and mechanical design, with the result as you type.

Capacitor code

Read the 3-digit capacitor code and get the capacitance in µF. 104 = 0.1 µF, 472 = 4.7 nF, and so on.

Resistor code

Read the 3-digit resistor code and get the resistance in kΩ. 103 = 10 kΩ, 472 = 4.7 kΩ, and so on.

Convert dB to ratio

Convert decibels into a voltage ratio and a power ratio. −3 dB = 0.707×, 20 dB = 10×, all worked out as you type.

Convert voltage ratio to dB

Convert a voltage ratio (V1/V2) into decibels. For amplifier gain and filter response measurements.

Convert power ratio to dB

Convert a power ratio (P1/P2) into decibels. For RF and amplifier design work.

Frequency ⇔ wavelength

Convert between frequency and wavelength, including the permittivity of the board. For antenna length and PCB transmission line design.

RC filter — cutoff frequency

Work out the cutoff frequency of an RC filter from the resistance and capacitance, and pick component values for a low-pass filter.

Resistor voltage divider

Calculate the mid-point voltage of a resistor divider, including the maximum and minimum once component tolerances are taken into account.

LED circuit design

Calculate the current limiting resistor for an LED. Get the current and its spread from the supply, the Vf and the resistor value.

Power consumption from current and voltage

Work out power consumption from current, voltage and duty cycle. For sizing a supply and for PWM or pulsed circuits.

Power supply efficiency

Calculate the conversion efficiency of a DC-DC converter or power supply from its input and output voltage and current.

Inverting amplifier

Calculate the gain of an op-amp inverting amplifier from the ratio of the feedback resistor to the input resistor.

Capacitance for a pulse current

Calculate the capacitance needed to supply a pulse of current, from the output current, voltage and duration.

Electricity cost from rated power

Estimate the running cost of a device from its rated power and hours of use. Get the cost per day, per month and per year.

Convert battery capacity in mAh to Wh

Convert a battery capacity in mAh to energy in Wh. For IoT and portable device design.

Propagation speed on a PCB from permittivity

Calculate signal propagation speed on a PCB in ps/mm from the relative permittivity. For timing analysis in high-speed design.

Trace resistance, heating, inductance and parasitic capacitance

Calculate the resistance, inductance, dissipation and parasitic capacitance of a PCB trace. For high-current and high-speed design.

Via and through-hole parasitics

Calculate the parasitic inductance and capacitance of a PCB via. For return path design on fast signals and for decoupling.

Skin effect

Calculate skin depth — how far current penetrates a conductor at a given frequency.

Characteristic impedance — microstrip (outer layer)

Calculate the characteristic impedance of a microstrip line, single-ended and differential, and pick a trace width for your stack-up.

Lumped or distributed

Find the boundary between lumped and distributed behaviour: the limiting trace length for a frequency, or the limiting frequency for a length.

Voltage drop across a resistance

Calculate the voltage drop across a resistance from Ohm’s law, V = I × R, given the resistance and the current.

Convert delay time to trace length

Work out the trace length that corresponds to a given propagation delay. For length matching and skew adjustment.

PCB weight

Calculate the weight of a printed circuit board. Get the laminate and copper mass from the outline size, layer count and copper thickness.

Convert oz to copper thickness

Convert PCB copper weight in ounces to thickness in µm and mm. 1 oz = 35 µm. For reading board specifications and setting up trace width rules.

Convert trace length to delay time

Calculate the propagation delay of a PCB trace from its length. For length matching and timing analysis.

Trace capacitance

Calculate the parasitic capacitance of an inner-layer PCB trace (stripline) in pF. For signal integrity and filter design.

Synchronous buck converter: efficiency, ripple and waveforms

Calculate duty cycle, efficiency and output ripple for a synchronous buck converter, and see the inductor current and output ripple waveforms.

FPGA/MCU I/O Buffer Standards & Drive Strength

A reference on FPGA/MCU I/O buffer standards (LVCMOS, LVTTL and more), how Xilinx, TI, Renesas and STM32 configure them differently, plus a calculator that estimates rise time from drive current and load capacitance.