This app is used to calculate the RC charging circuit and RC filter. It is suitable for hobbyist or electronic engineers. Features: 1. Calculate time constant by R and C 2. Calculate between time constant and % of charging 3. Calculate cutoff frequency of low-pass filter/ high-pass filter by resistor and capacitor values 4. To find out combinations of resistance and capacitance making a desired time constant 5. To find out combinations of resistance and capacitance making a desired cutoff fre