Ohm's law
Calculate voltage, current, resistance and power from two known values.
Electronics calculators
Fast calculations for circuits, components, power and signals.
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Series resistors
Add resistor values connected in series and calculate total resistance.
Parallel resistors
Calculate equivalent resistance for any number of parallel resistors.
LED series resistor
Choose an LED current-limiting resistor and check its minimum power rating.
Voltage divider
Calculate output voltage and current in an unloaded resistor divider.
Electrical power
Calculate power from voltage and current, plus energy for a given operating time.
Device energy cost
Estimate electricity use and operating cost over a selected period.
Battery runtime
Estimate runtime from battery capacity, load current and system efficiency.
Series and parallel capacitors
Calculate equivalent capacitance of a capacitor network.
RC time constant
Calculate the time constant and approximate capacitor charging time.
RC filter
Calculate cutoff frequency of a simple RC low-pass or high-pass filter.
LC resonance
Calculate the resonant frequency of an ideal LC circuit.
555 astable timer
Calculate frequency, period and duty cycle for a classic 555 astable oscillator.
555 monostable timer
Calculate the output pulse time of a 555 monostable circuit.
Wire voltage drop
Estimate wire resistance, voltage drop and power loss in a DC circuit.
AWG converter
Convert an AWG number to wire diameter and cross-sectional area.
Resistor color code
Decode a four-band resistor from its color bands.
SMD resistor code
Decode a common three- or four-digit SMD resistor marking.
Capacitor code
Convert a three-digit capacitor code into pF, nF and µF.
dBm to watts
Convert power expressed in dBm to mW and W.