The distinction between 2N3055 and TIP3055

[ebuka_2]

Are you are talking of the first or the second? B'cos I can remember that one of them is complicated.

 

[audioguru]

Are you are talking of the first or the second? B'cos I can remember that one of them is complicated.

On July 30th I posted the schematic of a 3000W modified sine-wave inverter. It has many parts but a sine-wave inverter that uses PWM is much more complicated.

 

[ebuka_2]

Someone told me that the output waveform of that 500W inverter in not really a square wave, and that it is close to sine wave. Is it true? If so, what then is the output waveform?

 

[audioguru]

I think the output is a square-wave because there is no tuned circuit to make it resonate. Even if there was a tuned circuit the load resistance is very low and would damp it so much that it would not resonate.

 

[Hero999]

It is possible to filter out the harmonics using a filter but a simple tuned circuit isn't really practical for the reasons you've already mentioned.

 

[Blatman Bond]

50Hz transformer are different from any flyback or switching transformer.
Their core won't response so fast to create square wave output.

Audioguru's schematic isn't PWM, nor a tuned output inverter. It has "modified sinus" title on it.

 

[audioguru]

A modified sine-wave is a square-wave with a step in it like this:

 

[Hero999]

One way of producing a modified sinewve is to use a DC-DC converter to boost the 12V to 320V DC then add an h-bridge to the output. Many cheap lightweight inverters use this technique. If you build an inverter with more than one output voltage you can have multiple steps in the output waveform which will reduce the harmonics even further.

 

[ebuka_2]

Yes of course there are better transistors than the old 2N3055.
But this simple and cheap square-wave inverter is used in The Philippines where the 2N3055 is available and better transistors are not.

Mosfets would be much better than transistiors in an inverter.

Please I am from Nigeria not philippines

 

[audioguru]

Are you going to design an inverter circuit that uses African transistors?

 

[ebuka_2]

Yes, if I may say

 

[ebuka_2]

Sorry for keeping out so long

I am sorry to have not said something this long, it was because of my exams. But I'm back now to continue with the project. Thank you very much for your previous contributions.

 

[ebuka_2]

Are you going to design an inverter circuit that uses African transistors?

Coming to that, I will like to, if it will still have the same or greater output power. In my country we use 220V at 50Hz. Thank you.