Re: Problem in inverter circuit
The problem with this 1950s-era multivibrator inverter is that it has absolutely no output voltage regulation.
The frequency will be all over the place.
Lastly to operate the transformer core is driven into saturation, which means terrible efficiency, high input current spikes, and transistor overheating.
Use a proper IC-driven design. The ubiquitous SG3525 was designed in the early 1980s, but it will allow you to build a far better inverter. There are tens of thousands of circuits on the web. Google it.