Need a circuit that is not here?
Describe it in plain English — “an Arduino reading a potentiometer and dimming an LED”, “a 12 V to 5 V regulator with a load” — and CircuPilot draws and simulates it.
LED Resistor CalculatorSeries resistor, power rating and real current for one or more LEDs.
555 Timer CalculatorAstable frequency, duty cycle, high and low time from R1, R2 and C.
Voltage Divider CalculatorOutput voltage with and without a load, current and resistor power.
RC Filter CalculatorCut-off frequency, time constant, gain and phase for RC low-pass and high-pass.