The distinction between 2N3055 and TIP3055

[audioguru]

I have many schematics for inverters. I don't know if they work.
The modified sine-wave ones use Mosfets and have a step in the square-wave. The transformer uses special voltages.

The pure sine-wave inverters are extremely complicated because they use pulse-width-modulation so that they don't get too hot.

 

[ebuka_2]

Thank you for the help so far. Please permit me to ask this question. Is there no how the square wave produced by the CD4047 can be converter to sine wave without affecting its output power?

 

[audioguru]

The CD4047 is a digital square-wave generator with a very low power output.
The transistors amplify its current.
The transistors switch on and off to stay cool.

If you feed a sine-wave to transistors and bias them so they produce a sine-wave output then they will waste a lot of power and get extremely hot.

Sine-wave inverters use a high frequency to switch their transistors on and off quickly and produce a sine-wave with pulse-width-modulation to stay cool. It is a complicated circuit.

 

[ebuka_2]

Thank you so much. One more thing; do you have an inverter schematic (12vDC-240VAC) with a power of 1000W or >500W. I need it, please give me if you have. Thank you

 

[audioguru]

do you have an inverter schematic (12vDC-240VAC) with a power of 1000W or >500W?

You need ten 2N3055 transistors, a huge transformer and a huge battery to make 500W.
You will need double that to make 1000W. Rediculous.

Here is a schematic for a 12V 3000W modified sine-wave inverter. It uses 20 Mosfets and hundreds of other parts.

 

[ebuka_2]

That is really complicated. Is there no how that you inverter can be uprated to 1000W or so.

 

[audioguru]

That is really complicated. Is there no how that you inverter can be uprated to 1000W or so?

I told you how, just double everything:
1) Use 20 or 22 2N3055 transistors.
2) Use an extra huge heatsink.
3) Usa an opamp with higher output current.
4) Use an extra huge transformer.
5) Use an extra huge battery.

The circuit won't need so many transistors if it is modified to use 24V as its input.

 

[ebuka_2]

Thanks

You said something about changing the opamp with one that has a higher output current, can you highlight the ones I may use. Secondly, what about the diodes, resistors, capacitors and fuse, will they be change too?

 

[audioguru]

I don't know any high output current opamps but they are available.
If you make an inverter with double the power of the schematic then of course the diodes and fuse must also have their current ratings doubled.
The resistors will have the same current and the capacitor also stays the same.

 

[ebuka_2]

Thank you I will get in touch. Thank you very very much.

 

[Bob Scott]

A 2N3055 is in a TO-3 metal case and can dissipate a max of 115W of heat if its heatsink is perfect.
A TIP3055 is in a TO-218 plastic case with a metal tab and can dissipate a max of only 90W of heat if its heatsink is perfect.

If the inverter is designed to use 2N3055 transistors then the heatsink or fan must be bigger if TIP3055 transistors are used.
You might need to add more transistors to divide the heat.

Audioguru,

The 2N3055 is a LOUSY old transistor. If you've ever seen that transistor's response on a semiconductor curve tracer you will agree. The output current rises with collector voltage. Hysteresis is visible on the curves as the current also rises with die temperature. I know that this old 70's technology just keeps on being popular and with some hobbyists just like the ancient 741 op-amp and the 555 timer that just won't die unless someone drives a stake through their hearts.

At least look at the 2N3773. This type is old too but at least the curves look decent (last time I looked circa 1982).

Regards,
Bob

 

[audioguru]

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.

 

[ebuka_2]

Audioguru
you said something about MOSFET being better than 2N3055 in inverter. What are the differences between them?

 

[audioguru]

Audioguru
you said something about MOSFET being better than 2N3055 in inverter. What are the differences between them?

An old 2N3055 transistor has a max saturation voltage of 3.0V when its collector current is only 10A but its base current is very high at 3.3A. Then it dissipates 30W of heat and its driver transistor also dissipates heat.

An IRFZ44 Mosfet (there are other better ones) has a max saturation voltage of only 0.28V when its drain current is 10A and its gate current is zero (but its gate voltage is 10V). Then it dissipates only 2.8W of heat. It can conduct 30A easily.

A 2N3055 transistor costs $1.68US for one at Digikey.
An IRFZ44 Mosfet costs $2.48US for one at Digikey. It is 10 times better for 1.5 times the price.

 

[ebuka_2]

If the CD4047 is changed with a PWM or sine wave generator IC, can it make a better PWM or sine wave inverter as the case may be.

 

[audioguru]

If the CD4047 is changed with a PWM or sine wave generator IC, can it make a better PWM or sine wave inverter as the case may be.

A PWM circuit is complicated but makes a good sine-wave inverter.

You can't use a sine-wave generator driving a linear amplifier. The output transistors will get extremely hot and waste half the power from the battery.

 

[Hero999]

I know that this old 70's technology just keeps on being popular and with some hobbyists just like the ancient 741 op-amp and the 555 timer that just won't die unless someone drives a stake through their hearts.

I can see your point about the 741, although I often use them for DC amplifiers as I've got loads of them in my junk box.

I disagree with you about the 555 timer, nothing is more usefull when all you want to do is generate a tone of a certain frequency, flash and LED of drive a relay for a few seconds. Programming PIC is a total waste of time for such simple tasks, besides what cheap PIC can both source and sink 200mA?

 

[Blatman Bond]

Hi Hero,
I agreed, 555 and 4047 are old. but they do almost everything in low freq square generator. Easy to find and very cheap. Did you have special memories with 555?

Hi Ebuka,
You may used 3000VA from audioguru's shematic as PWM (as hard switch). It using mosfet switch with charge pump for high side driving. Just replace the input with PWM (low freq PWM, 1KHz or near).

But better make it for low power first (might be just 10W). Its more save for your first try.

If the schematic too complicated, the PWM are more complicated. So, please do it step by step.

 

[ebuka_2]

I have seen it, but it is too complicated.

 

[audioguru]

I didn't post a complicated sine-wave PWM inverter. It was a simple modified sine-wave inverter without any PWM. Its waveform is a square-wave with a step in it.

A pure sine-wave inverter that uses PWM is much more complicated.