This is the schematic diagram of 300W power inverter circuit. The circuit use timer IC NE555 as to produce the wave / AC voltage signal. The signal the fed to the final amplifier to be amplified and to powered up the signal. There are many 2SD1047 transistor to amplify the signal. The transformer used to increase the voltage level to 110V or 220 refer to your needs.
Inverter, is an electronic device or circuitry that changes direct current (DC) to alternating current (AC). The input voltage, output voltage and frequency, and overall power handling depend on the design of the specific device or circuitry. The inverter does not produce any power; the power is provided by the DC source.
This 300W power inverter originally use 12V DC battery as the input and you’ll get 220V AC voltage.