Operation amplifier and voltage divider are the basic circuits for hobbyist or electronic engineers. This app is used to calculate all possible resistor values approximate a desired ratio Features: 1. Calculate resistor values of voltage divider 2. Calculate resistor values of inverting amplifier gain 3. Save component values in CSV file (Excel file) 4. Use preferred values of resistors Features in PRO version only: 1. No Ad 2. Can use preferred value 1% and 5% for resistor 3. No limitation