kachew

hi Au, can u recommen any better mosfet? thanks

hi Au, the IRF 540 mosfet only can withstand 23A only, then i need 3 mosfet on each side to withstand that large current or just simply 1 mosfet at each side cos 150W divided 12=15.7A???

dear au, can this step down transformer works? my friend had tried this method and it seems doesnt works.... i have ask the shopkeeper here...they said can make a step up transformer for which is custom made... i need the power of 150watts... now i become more confuse on the amps needed for me to choose the right transformer ??? :'( :'( ???

dear au, what u mean by this? i cant understand....last time u called me to buy a step up transformer...now u said i need a step down transformer???

dear au, i found from one of the inverter side and they given some formula which they have different calculations from you which is: 1) to convert amps to watt: multiply: amps*220(ac voltage)= watts which is my amps for the transformer will be approximately become 0.68amps for example, u have a freezer with a continous load of 4amps and start load of 12 amps: 4amps multiply 120volts=480watts continous 12amps multiply 120volts =1440 watts starting load after i calculate this result is very different from your result...can u explain the different between this..... as i know 15.7Amps transformer is very bulky and expensive....my motive is to make simple and check msw inverter.... can u help me on this?? thanks alots.... your help is highly appreaciated

dear au, sorry for my mistake, actually i need a transformer with 150W continous output, the rating for my transfomer is (8.5 to 8.5V) how about the amps i should buy for the transformer? izzit still the same 31.4amps? thanks ;D ;D

dear au, means that the output of the modified square wave will be a Vrms value? from the we multiply by square root of 2 to get the peak value? means 230 from the output of the transformer will multiply with square root 2 to get the peak value? what do u mean by this statement? how do you know that i must choose 8.5-8.5 instead of 10-0-10V transformer? can give me more explaination about this?? do i need to reduce the mosfet if i am making the 150w instead of 500w? as i know the mosfet is use for switching only....i think its doesnt affect much on the output value...?? thanks agian

deat au, yeah...wait i reattach the picture of the schematic to you pls give some comment and guide to me.... ;D ;D thanks

hi Au, yeah that's is what i want....can i implement it in the circuit with the cd4047 and cd4001? as i know the peak voltage of the sine wave is square root of 2 larger than the square wave....so which transformer i need to buy? (10-0-10) or the (12-0-12)? thanks

dear Au, so the transformer i need is the center tapped transformer(12-0-12 to 220V) with 15.7A multiply 2=31.4 or higher amps step up transformer for which to have continous power of 150W and surge capability of 300W with the overloading protection fuse (300W) to meet all my requirement? thanks again

Dear AU, the surge capability is the amount of the voltage needed to start an appliance....Multiply: WATTS X 2 = Starting Load, for inverter of output has 150W need to have a surge capabilty of 300W. how can i archieve that? by increasing the transfomer higher rating amps? (buy transformer that have more amps?).... i saw the inverter sold in the market which has rating of surge 300W but have overloading protection of 150W....so what is this means? i though is the inverter has the rating of 300W, it's aleady higher than the 150W how can the overloading protection can work appropiately? thanks

dear Au, can i know how much the current will flow to turn on the mosfet for switchin? and if i wan to get an output for 150W but not 600W but using the same circuit can it make it? as i know if i buy a smaller transformer as i asked the shopkeeper, the battery which supply 50A to the transformer which is 10A will blow the transformer off....can i know wat is the amps input will go to the transfomer? how can i calculate the output current of the transformer....i still cant get what u mean by previous post.... your help is highly appreciated.

dear Au, i know the transformer with small amps couldnt power anything....but the transformer with higer amps is very expensive in my country.....mayb i will use it for small applications such as charging my handphone or something else which need small amps.....do u think its ok? thanks

Dear Au, thanks for your explaination, can i buy transformer with lower amps? such as 12va or 30va for this circuit?

dear Au, means that the mosfet will draw 50A from the battery and each of the mosfet can withstand a current of 23A, so the current from battery will 50A divided by 3 mosfet so each of them draw 16.7A from the battry? is this what u mean? about the heating power ....how u know i will dissipate 100w? 1 more question, as i know the amps value also must take into consideration when wan to buy transformer....how can i know the amps value?

no no... i dint mean that....i mean how much mosfet will draw current from the battery? and what is the desired output Amps at the output of the trans? how we can determine the output amps....as i know the amps is dependent on how much load we have in the circuit..... any calculation can prove how many amps in the circuit and the output at the transfomer? thanks

dear AU, from your explaination i know abit of transformer thanks...but how can i know or make the output to have desire voltage regulation? but putting the desired value of resistor at the drain of the mosfet there? can u prove it by calculation so i can have better understanding on the circuit and the operation of the mosfet... thanks again

hi Au, how can i know how much currents flows in my circuit? izzit the same amount of current as shown in the datasheet for the mosfet? how many amps of current will flow to the transformer and what is the output amps and voltage as the modified sine wave circuit is recommeded by you....isnt the amps and voltage value for the circuit is controlled by the transformer? depends on the step up transformer voltage and amps rating since the mosfet is use to share and drawn current from the car battery? thanks for your reply... :-* :-*

hi eanic, nice circuit and thanks....:P

dear Au, i did the corrected version but still no avail, mayb the IC hav destroyed by me... cos i have wrongly connected the supply to the pin 13.... will it burn the ic? i will try with new IC of CD4047 to retry.... is there any other compatible IC can be used to replace this function generator IC? oh ya... i more question.... how can i modified the circuit and use the mosfet for amplification? as i know previous thread u told me that mosfet will get hot easily when amplification occur....so i have built another circuit which is 12V fan temperature control to cool my inverter circuit....can this be done?? thanks Au

dear Au, ooo mayb i did wrong already....i was been told by my fren on how to connect the probe...mayb because of this the ic burned...i try to buy a new cd 4047 and try to redo.... here i reattach the file....so u can check for me..... thanks Au

hi all, i have tried the CD 4047 and i cant get the desired output from the Oscilloscope....can anyone pls help me? i cant get the square wave pulse from it....i have connected a +12V supply and ground (which is connected to -VE supply with a wire) from a DC power supply at my lab. i have connect it according to the design....any mistake there...if yes pls help me to correct it.... thanks alot :-* :-*

dear steven, can i know the rating of the inverter? does the inverter need any transformer? what is output voltage and current for that inverter u shown?

dear steven, can i know the rating of the inverter? does the inverter need any transformer? what is output voltage and current for that inverter u shown?

hi audioguru, can i use a smaller trafo with more winding on it? i plan to make the trafo myself ;D