This is the free version, which contains ads; you can also buy from the Market the PRO version of the app to support the developer, unlock more features and get rid of the ads. The app includes: ? Resistor color code decoder (3-6 bands); ? SMD Resistor Code; ? Inductor color code decoder; ? Ohm?s law calculator; ? Reactance/Resonance calculator; ? Voltage divider; ? Resistors ratio, value/series/parallel; ? Capacitor charge calculation; ? Operational amplifier; ? LED resistor calculator; ? Adjustable voltage regulator/LM317 calculator; ? Heat dissipation;