Any linear bilateral circuit, which contain, G/R of same frequency the current that flows in any branch is the sum of the current's that would result from each G/R Working independently while other G/R.
Inverter is a device that converts 12 volts dc to 120 volts ac, which is what we use in our homes. This project will handle about 300 watts, which is perfect for lights, small T.V.'s and radio equipment. Read more about Inverter Project 12v DC to 120V AC
Transistors amplify current, for example they can be used to amplify the small output current from a logic chip so that it can operate a lamp, relay or other high current device. In many circuits a resistor is used to convert the changing current to a changing voltage, so the transistor is being used to amplify voltage. Read more about Transistor