Electronics
Ohm's law, resistor codes, voltage dividers and the sizing calculations of a bench workflow. 15 tools, including 555 timer calculator (astable & monostable), Antenna length calculator, Capacitor code calculator (decoder) and Capacitor energy calculator. All free, with no account and nothing to install.
555 timer calculator (astable & monostable)Design a 555 timer circuit in either mode. In astable mode, R1, R2 and C set the output frequency, high and low times and duty cycle; in monostable mode, R1 and C set the one-shot pulse width. The classic hobbyist chip, sized in seconds.Antenna length calculatorCut an antenna to the right size for any frequency. From the wavelength λ = c/f and a velocity factor, it sizes a half-wave dipole, quarter-wave vertical, 5/8-wave vertical or full-wave loop, returning the total length and the per-element length in both metres and feet.Capacitor code calculator (decoder)The three-digit code printed on a ceramic capacitor is picofarads: the first two digits times ten to the third. Enter the code (104 → 100 nF) and get the value in pF, nF and µF.Capacitor energy calculatorCompute the energy stored in a capacitor from its capacitance and voltage (E = ½CV²).Series capacitor calculatorCompute the total capacitance of capacitors connected in series.Impedance calculator (RLC)Compute the impedance of a series or parallel RLC circuit at any frequency. From R, L, C and f it returns the inductive and capacitive reactances, the impedance magnitude |Z|, the phase angle and the resonant frequency where the reactances cancel.Inductive reactance calculatorSolve the inductive reactance relation XL = 2πfL for any of its three variables. Choose whether to find the reactance, the frequency or the inductance, enter the other two, and it returns the answer — plus, if you supply an RMS voltage, the resulting current and reactive power.Inductor energy calculatorCompute the energy stored in an inductor from its inductance and current (E = ½LI²).LED resistor calculatorFind the series resistor needed to drive an LED from a supply voltage.LED savings calculatorCompare the running cost of old bulbs and LEDs and see your yearly saving.Ohm's Law CalculatorEnter any two of voltage, current, resistance and power and get the other two, with all 12 formula variants shown and an animated circuit whose charge carriers move with the current.PCB trace width calculator (IPC-2221)Size a printed-circuit-board trace for a given current using the IPC-2221 standard. Enter the current, the allowed temperature rise, the copper weight and whether the trace is external or internal, and it returns the required width in mils and millimetres — plus resistance and voltage drop if you give a length.Resistor Color Code CalculatorDecode 4, 5 and 6-band resistor color codes into resistance, tolerance and temperature coefficient.Parallel resistor calculatorCompute the total resistance of resistors connected in parallel.Series resistor calculatorCompute the total resistance of resistors connected in series.