Above scheme diagram is the circuit diagram of low budget, easy built low power power inverter designed using IC 556 as multivibrator and transistor TIP120 to amplify the signal from multivibrator.
This low power inverter consist of only 9 components and transform input voltage of 10 to 16 VDC into 60-Hz, 115-V squarewave power to supply AC electronic appliance with maximum power 25 W. The first section of the 556 timer chip is wired as an astable oscillator with R2 and C1 setting the frequency. The output is available at pin 5. The second section is wired as a phase inverter. That output is available at pin 9. Resistors R3 and R4 keep output transstors Q1 and Q2 from loading down the oscillator. The two transistors drive the transformer push-pull fashion. When one transistor is biased-on, the other is cut-off. The transformer used in this circuit is a 120 V/18 VCT unit that is connected backwards, so that this transformer steps the voltage up rather than down (work as step up transformer). Oscillator circuit U1, R1, R2, and C1 works from about 4 to 16 V with a extremely stable output.