The following article explains a pure sine wave inverter circuit using the IC 556 which forms the main sine wave processor device in the circuit.
How it Works
The presented design actually produces a modified sine wave output, but the waveform is highly processed and constitutes an exact equivalent of a sinusoidal waveform.
A single IC 556 forms the heart of the circuit and is responsible for manufacturing the required PWM controlled modified sine output waveform.
One half of the IC on the left is configured as a 200Hz frequency generator, this frequency is used for providing the required square wave clocks to the preceding monostable which is formed by wiring up the other half of the 556 IC.
The clocks are received from pin#5 and applied to pin#8 of the IC. The right hand side section of the IC does the actual processing of the above square wave by comparing it to the triangular waves applied at its pin#11.
The result is an output at pin#9 which is a PWM, varying in accordance with the amplitude of the triangular waveform.
Ideally the triangular waves can be replaced with a sine waveform, however since triangular waves are easier to generate, and also appropriately replaces the sine counterpart, its been employed here.
R1, R2, C1 should be appropriately selected so that pin#5 produces a 50% duty cycle, 200 Hz frequency.
The 200 Hz is not critical here, however it becomes critical for the IC 4017 stage and that's why it's been selected to that value.
The modified sine wave PWM generated by the IC556 is next applied to the switching stage comprising the IC 4017 and the relevant output mosfet devices. Let's see how it's done.
Parts List
IC1 = 556
R1,R2,C1 = select to generate 50% duty cycle
R3 = 1K
C2 = 10pF.
The output stage
The diagram given below shows the output stage configuration where the IC 4017 takes the center stage. Basically its function is to switch the driver transistors alternately so that the connected mosfets also conduct in tandem for inducing the required mains AC output into the transformer.
The IC receives the clock pulses from the above explained 556 circuit (pin#5/8) and its outputs sequence across the connected transistors alternately as discussed above.
Until here the circuit behaves like an ordinary square wave inverter, however the introduction of D1/D2 with the pin#9 of the 556 transforms the circuit into a full fledged pure sine wave inverter.
As can be seen, the common cathodes of D1/D2 are integrated with the processed PWM pulses from the above 556 stage, this forces D/D2 to conduct only during the negative pulses from the generated PWM blocks.
It simply means that when D1/D2 are forward biased, T1 and T2 are inhibited from conducting since their gates become grounded through D1/D2 into pin#9 of the IC 556, which make the mosfets respond exactly to the PWM pattern.
The above process generates an output across the transformer secondary that's perfectly chopped and processed and equivalent to a sine waveform.
Parts List
IC2 = 4017
all resistors are 1K
D1,D2 = 1N4148
T1,T2 = IRF540n
Transformer should be also appropriately rated as per the requirement.
The Triangular Wave Generator Circuit
The entire modified sine PWM waveform construction and implementation is dependent on the fed triangular waves at pin#11 of the IC556, therefore a triangle wave generator circuit becomes crucial and imperative.
However there are many types circuits that will provide you with the required waveform inputs, the following is one of them which incorporates yet another IC555 and is pretty simple to configure.
The output from the below given circuit must be fed to pin#11 of the IC556 for enabling the proposed sine wave inverter functioning.
DESIGNED BY "SWAGATAM"
A simpler alternative to the above design is shown below, the configuration would produce same results as explained above:
David Matthew says
Good afternoon sir hmm sir I build this circuit and alsudden the transformer start smoking and the 555ic1 get burn and it keeps blowing my 555timer I use 47nf instead of 50nf pls sir help me please
It started when I use 12v/7h battery
Swagatam says
Hello David, you must build the circuit stage-wise and confirm the working of all stages step by step, and only then integrate them together for the final results.
If you connect then all together then you might run into problems.
You might also require an oscilloscope to check the PWM waveform.
Nimel says
So what would be the importance of the 10k preset
Swagatam says
Both are used for setting up the output voltage
Nimel says
Pls sir what is the importance of the bc547, 1uf/25v capacitor and the 10k preset connected with the 1resistor and why was a 6v-0-6v transformer choosen
Swagatam says
Nimel, the BC547 is used to auto control the RMS voltage output of the inverter….6-0-6V transformer is dependent on the PWM level…you can use other transformers like 9-0-9V also and adjust the PWM accordingly through the right side 1k preset.
SAJI TR says
In complete many components value not mentioned
Sunshine says
Good day Engr. Please, I need circuit diagram of non-center tap inverter..
Swagatam says
Sunshine, please search for “full bridge inverter” in the search box
spencer says
Hello Mr. Swagatam Sir… I am a complete novice at this SPWM scenario. I have been reading and studying your circuits for a very long time… now..
So I discovered this website.. wherein you show and describe some very interesting circuits. So I tried to build up your rendition of the 3 … (7)555 timers and the 4017 combination.
So I started with the first timer – which is to be set at.. 200 Hz. Firstly after making up a breadboard build up… I never could get a 50% duty cycle waveform out. Instead I got… a spike pulse… negative going.. In your description I read that it must be a 50% duty cycle. So… I then decided to read the net… and found a datasheet… in which it described a 50% duty cycle waveform to be created… BUT your R2… 100 ohm.. is actually connected in the incorrect place. It should be connected directly from the +ve line… down to.. pin7 of the 555. This then gives a perfect 50% duty cycle…
SO I carried on… I then built up the second timer… obtained the waveforms.. but could not get a stable waveform of 200 Hz, and 500 Hz… So Mr. Swagatam Sir… I employed my FLOWCODE 8 program… and a simple PIC12F675.. 8 pin chip.. and wrote and timed a loop in which I succeeded in getting a dead accurate – 200 Hz and 500 Hz square waveform..
I then used.. a mosfet transistor with 2… 10K resistors per fet..(2N 7000).. to make up a level convertor… so that the PIC output could be level shifted to 12 volts of the +ve line. All this works perfectly… now… I would like to send you what I have done.. You may also download the FLOWCODE 8 program from the UK servers.. and use it for free for a month.. If you would like to purchase it.. please contact me first – I have an option which could help.. (NOTHING ILLEGAL IS INTENDED)…
So now the Mr. Swagatam.. Sir.. I carried on.. I built up the 3rd timer chip… with the idea of trying to get it to give me the triangle waveform – I suppose on pin3 of that chip.!!
BUT alas Sir… here I am completely stumped…!!!.. does a triangle waveform.. come out of pin3…?? the position of the 100 ohm resistor, on pin7 of the timer chip… is that correct.. Is the value of the capacitor that is being charged by constant current charger… comprising.. BC557,D1,R3,R4,C3..is it 1ufd..??.. and does there come a 500 Hz square wave pulse of 50% into that timer…?? or is it merely a spike pulse… on pin2..???.. I do not know what is sposed to be happeneing in that circuit.. Does pin3 output … show a 500 Hz.. triangle waveform.. or is it.. a slow … properly formed.. ramped up / ramped down… triangle waveform..?? I just do not know what I must expect.. The position of R5 in the circuit… where must it be… ??? where it is drawn.. or in another position to produce a 50% output..??? I really do not know what I must expect…
Please Mr. Swagatam… can you show me the waveforms which must appear on pin3 of that timer… ?? and also at what frequency… why do you select 500 Hz… I thought 200 Hz… should be enough.. I do not know…?? please can you help me… I so wish to get this project working…
I really would appreciate an email to help me with my stupidity… I tried to get help locally but it seems I am on my own…
Oh yes.. I am a pensioner… and 70 years old… and I live in South Africa… we are at war now with the CORONA VIRUS… Oh my goodness Sir… !!
Hope to read a reply… possibly from you…
My very Kindest Regards
Spencer…
Swagatam says
Hello Spencer, the center IC 555 diagram in the above article is correct. The 100 ohm is placed to generate square wave at 99% duty cycle, so the triangle waves are properly generated. The triangle wave are generated at pin6 of right side IC 555. This happens when C3 at pin7 of this 555 IC is charged/discharged alternately by the 99% duty cycle square wave from the middle IC pin2. This triangle wave is compared by the voltage level at pin5 of the right side 555 IC, and the resultant PWM created at its pin3 is used for chopping the MOSFET gates and for achieving the desired output RMS.
I think PIC would be an overkill for this simple project which could be implemented with cheap IC 555s, although I truly appreciate your interest and effort in developing the PIC codes, it is not easy.
And yes the extreme left side IC is not configured for 50% frequency, and must be modified as per your suggestions
Spencer says
Hello Mr. Swagatam .. Sir..!! – I will try again… so I built up the “middle IC” … with those components.. and I set it to ‘work’.. at 500 Hz… (500 Hz… is the correct frequency..???? – YES..??? ).. and I see that for most of the time… the output pulse is high..(at pin3)… with about a 5 usec width… negative going pulse… which is fed into pin 2… (which will trigger the right side 555 IC…)..
Thank you Sir… I will also add at least the 1K pot to pin5 of that IC… so that I can vary it for changing the voltage on pin5..(CV).. and see what happens…
I would ask… Sir.. you (and others).. to test FLOWCODE… I am not an agent… I am a pensioner.. I do not know C-code.. that is why I am ‘mad’ about FLOWCODE.. it helps me manufacture … the most amazing microprocessor projects.. with absolute ease… be surprised…!!!!..
Thanks again.. for responding so quickly.. I appreciate…!!..
Kindest Regards
ole Spens …
Swagatam says
Yes the 500 Hz is approximately correct but around 300 Hz will be better since lesser frequency will create lesser heating in the iron core transformer. This frequency decides the number of pillars the output PWM will have.
Sorry I have no idea about flow codes so it won’t be possible for me to verify your codes.
dele lukman says
good day sir, i have add voltage regulator to the cct and as i adjust the 10k preset the out voltage is varying 220v to 235v but there was a serious electric shock on the both side of the battery that is negative and positive terminal of the battery.
Secondly i would like u to tell me where to put indicator to show that the battery has shut down due to low voltage, you have told me how to shut down already which i have done.
Swagatam says
Yes the circuit is not isolated so the entire circuit will have electric shock. To avoid this you can use a small transformer power supply. The 1M will now become 1K. The transformer 220V will go to inverter 220V, the 0-12V output will need to rectified and filtered and then applied to the resistive network
for low batt indication you can include the following circuit
https://www.homemade-circuits.com/low-battery-indicator-circuit-using-two/
BrianR says
Sir Good day, is the modified sine wave circuit above applicable to H bridge / Full bridge? i would like to try this build. i have a transformer 33A with single 12.5v no CT / 220v . i want to use my spare x14 IRF3205.
thanks
BrianR
Swagatam says
Hi Brian, yes the output could be used with a H bridge built with P channel, N channel MOSFET….4 N channel cannot be used
dele lukman says
Thanks sir the information has solve my problem.
sir, whenever i test the output of the inverter without load , my meter is usually damage and i tries to apply capacitor across the output the meter was not damage but there was noisy of trafo which i am not satisfy with although the noice dissapear as i apply load.
secondly sir, if i put on tv or fan the light blink with 500va, 8v=0v=8v, 220v trafo Help me out sir
Swagatam says
Hi dele,
what is the output voltage you see without load? Please check out the last diagram, and add the voltage regulator circuit as shown, and adjust the output at 230V using the 10K preset
Faith says
Good afternoon sir, please I need your assistance I’m building an inverter, which I presume to be sin wave because I’m using the principal of spwm which I read in one of your blog where you said passing two triangular wave (fast and slow) form through a comparator the output waveform form wil be a spwm, this I have achieved, my next step which I will do today is passing this spwm together with the one coming from the sg3524 and I intend building a 24v inverter which I’m using transformer of 14v now my question is this is there any way of using a voltage doubler so that I can charge my battery using this same transformer
Swagatam says
Faith, you will need 28V to charge a 24V battery, and you can get it through a boost converter circuit and it should be well calculated and very efficient.
Faith says
Ok sir do u have boost circuit in any of your blog, again I have some waveform from my oscilloscope which I get when passing an spwm together with the waveform from sg3524 through a transistor please can u give a mail were to send it so that you assess it to see if it ok to work with
Faith says
Please sir I don’t understand what you mean by” If you are using external an SPWM then your SG3524 PWM control must remain fixed at a maximum possible level” I have send the image thanks
Best regards
Swagatam says
The SPWM is not a part of the SG3524 IC therefore it is externally applied.
Swagatam says
Faith, I saw the pics, the SPWM looks OK, did you get the slow triangle from SG3524 RC network? Please show the schematic so that I can understand better!
faith jumbo says
I got both fast and slow from 555timer sir please the 3rd and 4th is gotten as a result of both waveform from sg3524 and lm358 and is the waveform going to the gate of the mosfet which among the two is better I will forward the circuit now
Swagatam says
Please do exactly what I say below:
Remove the SPWM from the mosfet.
adjust the sg3524 duty cycle so that it produces maximum voltage square at the MOSFEt gates.
Remove the IC 555 slow triangle wave input to the LM358, instead get the slow triangle wave from the Ct terminal of the IC SG3524.
After this check the waveform at the output of the LM358, if you find it perfect, then connect it with the transistor buffer of the MOSFET. You must use a transistor buffer before the MOSFET
faith jumbo says
Hi good evening sir please I want to generate a triangular wave with 555timer please do have any circuit of such please I need help
Swagatam says
Hi Faith, you can use an IC 555 astable circuit, where the junction between the resistor and the capacitor will give you the required triangle waves
Faith says
Thanks I have already gotten what I want
faith jumbo says
Ok sir I will do that immediately i get home but which pin of the sg3524 will I get the slow triangular waveform and yes I use transistor buffer it is at the output of the transistor I got the 3rd and 4th waveform
Swagatam says
Pin#5 is Ct.
First check the waveform at this pin to confirm it is 50 Hz triangle wave.
Faith says
Ok sir that means only pin 4 and pin8 will be taken to ground
Swagatam says
for which IC?
Faith says
Sg35254
Faith says
Sir I hv don what you ask me to do but waveform is not good at all so what I did is that I modify the circuit i.e the 555timer and I got a better spwm which I Will send to you, sir I notice that at the output of the buffer the waveform coming out is spwm is this right? Again what frequency I’m my suppose to get at the output of the buffer I will send you the output waveform from the buffer also
Swagatam says
Please refer to the following article:
https://www.homemade-circuits.com/how-to-generate-sinewave-pwm/
Your SPWM should be in this form.
dele lukman says
pls sir i have construct this cct to carry my load for the past two weeks now but i discovered that trafo is getting hot easily while mosfet tempereture is ok
Swagatam says
The transformer can mostly become hot if the DC side winding rating is much lower than the mosfet drain voltage
dele lukman says
……and i have tried to regulate the supply voltage to 10v, only ic2 is not respond
dele lukman says
Good day sir,
with 12v\7ah battery my cct is working fine but whenever i connect it to 12v\100ah battery ic2 is gust blowing. Pls help me out sir
Swagatam says
Hi Dele, connect the IC side circuit through a 100 or 220 ohm resistor, also connect a 1000F capacitor across the positive/ground line of the IC section, and see if that helps or not?
dele lukman says
i have done the cct and it work perfectly, the frequency and voltage at output of trafo is 50hz and 220v respectively. No issue of noisy trafo any more.
May God bless u and ur entire family.
Swagatam says
That sounds wonderful dele, appreciate your feedback very much!!
dele lukman says
Good day sir,
pls where is the best position to put SCR if i had to shut down this cct against LVD.
Is it compulsory to put capacitor at output of trafo
Swagatam says
Good day dele, you can connect pin#15 with pin#10 with a 10K resistor. Then connect the cathode of the SCR with pin#15, anode to positive line…so that when a gate trigger is given to the SCR the system will completely shut down.
dele lukman says
hi Swagatam,
pls sir, i would like to know the type of capacitors used in various point of your design, also to asks why standard operating frequency{50hz} is not so important that you did not consider it in the cct, and also to know why battery voltage is not regulated for the cct
thanks sir
Swagatam says
Hi dele,
the output will be a 50 Hz, I have made sure that it gives 50 Hz by recommending 200Hz at the 4017 input. I have a feedback included in the lat diagram which will probably take care of a discharging battery and help to keep the output constant
Solomon says
Hello sir, i asked some questions in one of ur post and i see no reply, let me ask u the same questions here:
1. In choosing or selecting MOSFETs, what must i consider, is it the volt or the amp of the MOSFETs?
2. Can i use stabilizer transformer to connect with my inverter circuit?, or does a stabilizer and inverter has different pattern of winding
iyiola semiu says
Gud job boss
Shadmehr Aria says
Hi,I want to convert 310 VDC to pure sine wave 220 VAC using 4 N-channel mosfet IRF740 or IRF830,I already made it with AVR and IR2110,but now I want to use no microcontroller,Would you please help me doing this job?Regards.
Swagatam says
you can try the following circuit:
https://www.homemade-circuits.com/2014/01/simplest-full-bridge-inverter-circuit.html
Sudhee Krishnan B says
THANKU SIR FOR YOUR REPLY… HERE I USED A 12-0-12/ 230V, 5A TRANSFORMER.. AND I AM GETTING ONLY 120V OUTPUT. FROM THE ABOVE COMMENTS I HAD UNDERSTOOD THAT I SHOULD USE 6-0-6/ 230V 5A TRANSFORMER. I WILL REPLACE THE TRANSFORMER SOON.. THANKU…. I WILL BE BACT IF THEIR ANY DOUTS ARISES….. THANKU
Sudhee Krishnan B says
am getting an outputvoltage of 120v. i had used irfp55 as mosfet.i need 220 volt out put. in the circuit diagram u had given in the output that it will give 120 v or 220v.what change to be done to get 220v output
Swagatam says
remove the PWM diode connection from the mosfet gate and check the voltage, if you see it to be 220V … connect back the PWM and adjust the pin5 preset of IC2 until the voltage settles to 220V,
if you are using a 12V battery then make sure the transformer is either 6-0-6V or 9-0-9V
Sudhee Krishnan B says
i had wired up the circuit.. i had used irfp55 as the mosfet,.. am getting only 120v output…….
daniel adusei says
sir please i build this circuit and got 6.8v at output of ne555 and i got 5.8v at ne556 output cd 4017 i got 2.3v at pin2 and pin7 how can do to raise up pin2 and pin7 lik 4v to maybe 5v cos the circuit don't start i think it the out put of 4017 is too small to open the gat of the mosfet, sir i found 4017 circuit its the same as this one but the different is you added transistors at pin2 and pin7 but you did not put value of the component thank you.
Swagatam says
you are seeing the average voltage in your meter…the peak voltage should be well close to the supply voltage…so it's perfectly OK for triggering the mosfets
Dinesh says
Hello sir,
I want to make a circuit for 8kHz sine wave. Can you plz post a suitable circuit with correct component values?
thanks!
khang ly says
hi sir
you received my picture
Swagatam says
No, did not receive any new pictures??
khang ly says
hi sir
i will sending you any my picture. this is results
It output not pure sin. I'm wrong in area ?
specifiction tranfo 12-0-12 =>220v ,i'm supply 24vdc,output 20vac – 30vac,
i'm supply 21.9vdc, output 204vac
output tranfo i connect a 0.33uf/400 but it not pure sin
Swagatam says
hi khang, did you put a load at the output? please put a load and then check.
anyway you won't get a pure sine wave rather only as shown in this article:
https://www.homemade-circuits.com/2013/10/modified-sine-wave-inverter-circuit.html
you can also try connecting an inductor after the capacitor as shown in the above article….
Peter Anongo says
After using the link "www.royalrife.com/555_calculator.html" I've come up with the following values: R1=100 OHMS, R2=10K, C1=330nF which gives a frequency of 217Hz and a duty cycle of 50.2%. Will this work? Am trying as much as possible to work with parts i already have. Thanks.
Swagatam says
At IC1 pin3 it should be around 500Hz, at 4017 pin 14, it should be 200Hz
khang ly says
hi sir
you received my picture.can you help me
thanks
Swagatam says
hi khang, yes i saw them, please check it after connecting a load and also connect a 0.22uF/400V capacitor across the output terminals of the transformer.
please check the response with the above.
khang ly says
hi sir
i'm check again and let you know the results.
thanks
khang ly says
hi sir
yes .i will sending to you
thanks very much
khang ly says
hi sir
im tweak them perfect. i use 12-0-12 out 220vac tranfo.
DC input 12v .but output tranfo give me 120vac 50hz it's not pure sine, it's give me spikes pulse
can i connect RC filter for output tranfo sine pulse . it's is value
thanks
Swagatam says
Hi khang,
you must use a 6-0-6 trafo for a 12V battery.
anyway how did you check the spikes, I guess you checked them on a scope, can you please send the images for verification??
yes filters can be used but that will make the fets hot.
khang ly says
hi sir
thanks .im check again . i try tweak them
khang ly says
hi sir
i have a question
pins rest not use (IC 4017) is open or connected to each other
Swagatam says
the remaining outputs are all unused and open.
khang ly says
hi sir
I have followed the guide but circuit operation not good. output 80Vac and 200hz, i can't control accurate frequency in circuit . i adjust frequency IC1, IC2 frequency change too,
can you help me
Swagatam says
Hi Khang,
the above circuits are perfect, may be you are not able to tweak them rightly.
you can try the following design instead:
https://www.homemade-circuits.com/2013/10/pure-sine-wave-inverter-circuit-using.html
khang ly says
hi sir
i have a idea
can you use wien or pubda bridge circuit to generator true sine . sine pulse input pin 14 ic 4017
thanks
Swagatam says
hi khang, it's not pubda, it's bubba oscillator.
pwm sine is more efficient than bubba sine concept
my previous simple sine wave inverter was based on the same principle (bubba)
https://www.homemade-circuits.com/2013/04/simple-pure-sine-wave-inverter-circuit.html
khang ly says
hi sir
thanks for relay.im check again.
frequency in ic 1 and ic 2 (7555) not stabilize.
pulse in ic1 and ic 2(7555) is spike pulse and very noise
output 2-7 ic 4017 is square pulse not sine pulse
ic ne555 Specifications not good i think so
Swagatam says
Hi Khang,
everything is perfect in the circuit, it's done as per the datasheet info of the IC 555, for the waveform images you can refer to the following article:
https://www.homemade-circuits.com/2013/10/modified-sine-wave-inverter-circuit.html
Khang Ly says
hi sir
can you tell me out put pin 3 ic 7555(1) what is pulse? spuare or triangle…
out put Ic7555(2)is pulse ?
help me. thanks
Swagatam says
it will be a square or a rectangle pulse
khang ly says
hi Swagatam majumdar
im construction your design (three ic 555) but i can't control frequency 200hz and 500hz . your design in generator frequency have problem , can you update for me ?. can you help me ?
Swagatam says
Hi khang, I don't think so, the 555 section was published in elektor electronics magazine so it can't be wrong moreover i have tested it for a motor control design, it worked perfectly…the same has been applied here.
try using a lower value for the 50nF, make it 22nF or lower and check the response.
Swagatam says
yes definitely
khang ly says
can i use three ic 555
khang ly says
hi Swagatam Majumdar
image not risk
c3 in ic2 7555 is val?
is 1mF?
Swagatam says
Hi khang, yes it's 1uF
Peter Anongo says
Hi Swagatam. Have you tested this circuit and confirmed it to be working? Is this circuit suitable for digital electronics (PC, Led TV)?
Swagatam says
Not yet Peter, but I am sure about its results, it will work if done correctly. It's suitable for all sophisticated equipment.
khang ly says
Hi Swagatam Majumdar
sorry i have a question stupid
output is true sine or square pulse
Swagatam says
Hi khang, it's a true sine.
Anurag says
your circuits are really innovative
Swagatam says
thank you!
franco rossi says
dear Swagatam Majumdar,
in the explanation of the circuit comes to T3 but I can not find it on the diagram.
you can tell me where it is?
thanks
greetings andrea
Swagatam says
Dear Andrea, goo observation, thanks.
Actually T3 has been removed in the above updated diagram.
In the previous design T3 was connected with the common cathodes of D1, D2, however later I realized that T3 was in-fact inverting the PWMs which would cause incorrect results at the output of TR2.
Therefore I did the necessary corrections and removed it from the diagram.
……..I'll remove it from the article too, shortly.
Swagatam says
…by TR2 I mean the transformer shown in the diagram:)
biannz says
sir please in the last circuit ca i use 4n35 opto?
sir please it this a pure sine and ca it be use for long period i mean always without switching off?
sir can ne555 replace this ic (7)555? if i use ne555 can it produce same as (7)555?
please sir .
biannz says
sir please the link you gave don't work please resend again thank you
Swagatam says
the links is perfect and works, copy it correctly.
biannz says
sir thank you sir please this circuit, from ic556,ic4017 and NE555 it work but the problem is the two fets got hot,sir im asking you that i use (1k for R1) i use (10k for R2) and (104 for C1) in NE555 i did not get 62k so replace it with 68k so sir it becos of that im experiences all the problem? sir my question is it 20k preset use for 220v output or for frequency? please i need your assistance sir its this pure sine wave?
Swagatam says
biannz, the parets used are approximately correct.
I will recommed you to use te following circuit for the triangle wave generation:
http://www.next.gr/uploads/544-18813c9c29.gif
C = 0.1uF
the mosfets should not become hot without any load at the trafo output
biannz says
ok sir but please in the ic 556 where is pin3 of 556 connect to?
Swagatam says
it's unused
biannz says
sir please i want to ask you that in this circuit Make this IC 556 Pure Sine Wave Inverter circuit from firs circuit to third circuit should be connect together?
Swagatam says
yes, these three stages will integrate with each other as per the given instructions.
biannz says
sir please im going for the 556 and 555 sir you said pin 11 of 556 should connect to 555 out put in the 555 it need to be power so im asking 555 can be power by 12v BATT or it need 6v supply? sir please im talking about this circuit The triangular Wave Generator Circuit
Swagatam says
biannz, you can use 12V for the triangular wave generator circuit.
biannz says
sir please im going for the 556 and 555 sir you said pin 11 of 556 should connect to 555 out put in the 555 it need to be power so im asking 555 can be power by 12v BATT or it need 6v supply?
Swagatam says
I did not understand your question….which circuit are you referring to?
555 wii work with 12V
biannz says
sir why me i did it exactly as you said but still heating and blowing the transistors i chick every pats of the circuit nothing seem to be wrong sir i even build it Sevres times and it have cost me a lots cos our electronic pats are not chip at all sir have you ever build this circuit before do you have it pcb? sir i use 250k preset in place of 180k cos i did not get 220k preset,in my country we only have 10k pot,2kpot,2.2k pot 4.7k pot 50k pot 100k pot 500k pot we don't sell 180kpot or 220kpot no.sir please i dont care how much it going to cost me i still want to survive help me sir cos im going mad sir thank you looking forward to hear from you.
Swagatam says
bianzz, don't depend on me, i advised this to you once before…ask the questions to yourself why you are not succeeding. If you are not able to troubleshoot the problems yourself means you have not understood the circuit, or may be this circuit is not for you.
If you are having difficulty in making this design, there are many simper circuits in this blog you can try those and learn from the scratch..
All components indicated in the diagram will need to be as given, the parts values cannot be compromised.
biannz says
ok thank you im very appreciate of it the way you responds my quotations but sir in the last circuit i finally build but the transistor got hots without plugin any load sir i need your help thank you looking forward to hear from you son.
Swagatam says
Biannz, that can never happen as long as your 4017 IC is sequencing correctly in response to the clocks at it's pin14. Or alternatively you can try connecting TIP122 transistors and a smaller trafo initially for confirming all the circuit functioning as per the explained specs. If the TIP122 also becomes hot would indicate some other issue with your circuit design
you can also try using 3V zener diodes in between the mosfet gate resistors and IC4017 pinouts, this will ensure complete switch OFF of the mosfets when the pinouts are at zero potential.
biannz says
sir please i want to ask you that is it compulsory to use opto i mean to put there the ldr and led? its the circuit going to work if i did not ues LDR AND LED? thank you.
Swagatam says
You can use it only if you want to get an automatic voltage regulation.
biannz says
sir please the last circuit what is the per pose of the opto? can i use opto 4n35 or LDR and LED combination? thank you sir hope to hear from you son.
Swagatam says
only led/ldr combination will work, 4n35 will not work
biannz says
sir the lats circuit that use 3 ics (555) can i replace 47nf in place of 50nf? and also the two preset 180k can be remove and use 180 resister? sir is not that i am not follow your circuit but some of the pats lists or component are very difficult to find it that's why so forgive me for bordering you thank you sir im looking forward to hear from you son.
Swagatam says
I think we have already discussed this question earlier, 47nF can be used for 50nF and 180k can be replaced with 220K preset.
how can you use 180k fixed resistor when it's clearly shown as a preset and is crucial for setting the frequencies??
Pat Selim says
Hi, could I expand this circuit to include as many transistors as necessary, in parallel, to get a higher wattage?
Swagatam says
yes surely you can do it.
biannz says
hi sir please sorry for the question ok cos i really like your skills of creating circuits especially the inverters circuit,my question is in this circuit Make this IC 556 Pure Sine Wave Inverter circuit can i replace NE555 in place of 556? its this a real pure sine wave as its named? thank you sir.
Swagatam says
Hi bianzz,
please see the last diagram, you can do it in that way. It's a modified sine wave, equivalent to a pure sine wave.
Pat Selim says
Great circuit, however I read somewhere that it's always good practice to put a rather large capacitor on the primary transformer stage so as to avoid "dirty" AC. But you didn't include it ? Also, you don't explain, really, how a PWM waveform is somehow coverted into sine wave at the secundary stage
Swagatam says
Thanks! I have included only the crucial things in the designs, ofcourse it can be enhanced in many different ways, I leave it upto the readers to do them as per their own preferences and knowledge levels.
The PWM is manufactured inside the opamp of the 555 IC by comparing the external square waves and the triangle waves across the 555 capacitor.
ibitoye isaac says
swagatam you are great i love every page of your articles
Swagatam says
thank you ibitoye!
Siddhant Shrivastava says
thank u very much i was tooo much confused that how to design inverter bt nw i got idea
bt which transformer to be use ???
Swagatam says
transformer should be ideally a 9-0-9V and wattage as per load requirements.
Arnab Dasgupta says
Hi Swagatam,
I have gone through several inverter circuits in this blog and i wish to make one of my own. I have tried to make inverter in the past but i faced one major problem of the output transformer. I have confusion regarding this matter. Is there anything called "Inverter Transformer" of particular rating? I asked many but none of them gave me a suitable answer. Can i get it readymade ? Do i have to manufacture of my own? It will be extremely helpful for me if you kindly clear my confusion.
Swagatam says
Hi Arnab,
There's nothing called "inverter transformer" you can use any ordinary transformer having one side winding matching the battery voltage while the other side winding corresponding to 220V, that's all is required….current rating of the transformer will correspond to the load that needs to be operated, higher rating would allow higher loads and vice versa.
Sudhee Krishnan B says
sir,u are saying that one side of the transformer should match with the battery voltage.then how can one use 6 0 6 /230v or 9 0 9/230v for a 12v battery supply…?
Swagatam says
6-0-6 is a matching transformer when a PWM is used, otherwise 9-0-9 is a matching spec,
here matching does not mean that it should be exactly the same.
Swagatam says
…it is not necessary if the supply is constant.
Swagatam says
Hi Robin,
It just a constant current configuration so that the IC2 does not get affected with supply voltage variations and current up-downs.
It is not necessary, you can remove the zener, the 470 resistor, and the transistor and just connect the positive resistor to the IC pins directly
Swagatam says
yes it can be done by using input voltages upto 60/100v and by using transformer/mosfets capable of handling 2000 watts of power
SHIV-FOUNTAIN says
hi dear swagatam can you please tell us which type of capacitiors used in all digram whether they are porcelain or ceramic.since while buying componenet they ask me which type capacitior you want.is there major change in result if i buy wrong type capacitior.
Swagatam says
I answered this in G+
Swagatam says
I have simplified the circuit to a great extent in the last diagram, you can try it.
vishwas poojary k says
NO two or more gates of mosfets can be directly connected , if we do so mosfet gets blow off, we must connect each through 47ohm resistor..
vishwas poojary k says
we can istall visual analyser softeware in pc , den we can use pc as oscillocsope (20hz to 20khz) .. input is mic input in sound card , appropriate strobe must prepared , use o.1u capacitor , 1M ohm resistor in serias with phase for 220 v ..
vishwas poojary k says
ok.. sir can u try the above circuit practically in small scale(in your free time) ??
Swagatam says
you can use single mosfets IRf540 for each channel as shown
Swagatam says
You have made a good point, the last circuit is actually not set for producing 50Hz, IC1 parts will need to be changed for setting up this frequency. I'll do it soon.
Also I have added a RMS correction preset to the last circuit, I hope you have seen it.
avijeet agrawal says
Thanks for ur reply sir
At last ,there is no any Preset used in above circuit so this circuit is fixed to produce 50hz 220v at output(approx).
which mosfet i had to use and how much on each channel for 750watt trafo
(I had couple of irfp250, urfz44,irf540,irf54n06)
Thanks
Swagatam says
both types will work, you can use 555 or 7(555) doesn't make any difference.
473 = 47000pF = 47nF, so that's fine, you can use it.
3V zener will be ok!
avijeet agrawal says
Thanks for ur reply sir
So will u suggest me to use ic555 instead of ic7555 for above circuit u had discussed at end of above article.
Some more doubt i want to clear it with u
#can i use 473 instead of 50 nf capacitor.
#can 2.7v zenner will replaced with 3 v zenner
Michael M. says
Hi Sir,
first I want to express my respect to you, answering all the questions here.
My Name is Michael. I only want to ask a Special question……is it possible to immitate a tapped tranformer, with 2 equal resistors connected in series, which to connect both parallel to trafo to get a middle Point ? Only a thought….might be a weired one 🙂
Swagatam says
Hi Michael,
no that will not work, because the voltage has to pass through the winding in a push pull manner in order to generate the output voltage.
Swagatam says
7555 consumes less current and its output is more accurate than the analogue IC555, but IC555 is able to output 200mA current which the cmos counterpart cannot….so according to me IC555 is much better than (7)555, however it largely depends on the specific application, which one suits it better.
avijeet agrawal says
Thanks for ur reply sir,
At the last in above article u had posted a circuit having two (7)555ic and one 4017ic.
Is 555ic and (7)555ic has some difference in their working.
I had read some where that 7555ic has a diffrent packaging (cmos) type.can i use normal ne555 ic for above circuit
Thanks
avijeet agrawal says
Thanks for ur reply sir,
At the last in above article u had posted a circuit having two (7)555ic and one 4017ic.
Is 555ic and (7)555ic has some difference in their working.
I had read some where that 7555ic has a diffrent packaging (cmos) type.can i use normal ne555 ic for above circuit
Thanks
Swagatam says
you will have to try it practically for confirming!
Swagatam says
thanks! this circuit will work only with center tapped trafos.