Online calculator collection:
Linear regulators	LM317-Current-Calculator
	LM317-Voltage-Calculator
	LM337-Voltage-Calculator
SMPS regulators	LM2576 Design Calculator
	MC34063 Design Calculator
	TL494 Design Calculator
Filters	RC Low-pass Filter Design Tool
	Active Bessel Highpass Filter Calculator
	Active Butterworth Lowpass Filter Calculator
	Active Butterworth Bandpass Filter Calculator
	Free Filter calculators
Others	Trace Width Calculator
	Wire Parameter Calculator
	Thermal Resistance
	Coil Inductance Calculator
	Differential amplifier calculator