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Everything posted by kachew

  1. hi au, how about the voltage spikes caps near the transformer? izzit the ceramic type too?
  2. hi, the capacitors for the voltage spikes is AC caps or Dc caps? thanks
  3. hi au, how do u choose, how u know what value of the resistors and capcitors for voltage spikes? the value of the capacitors and zener diode across the power supply of the ic? any formulas? thanks
  4. Dear Au, the ceramic disc capacitor is still there....which is parallel with the zener diode ;D ;D
  5. hi au, the CD 4047 ic is burning at 1st it can be used for generating pulse but later when i turn off the power supply from the lab...it seems burn and i use OSC to check the waveform and there is only noise no longer have any square wave in it...the DC supply in is 12 volt but after i connected to the inverter circuit and transformer for amplification the reading on the power supply drop to 5V and the current goes high... is this is the modification u meant?
  6. dear AU , yup i know...but the osc result doesnt have the required result....i tried many times....at last i will get the same square wave form....but this is ok... the main things is the ic burn many times....although i have use diff grounding and bigger size wire....can u recommend me a regulator which suit to the ic? i think this is the most efficient way....can i voltage regulator to regulate current? as i know regulator is to regulate voltage only
  7. dear au, ooo can u recommend me a voltage regulator? regulate to the ic.....so that the ic will be protected from being burn....thanks
  8. dear au, yes i have separated the ic wires to the battery connection and the heavy wires from mosfet to the ground and the to battery....but the problem is the ic need to be connected to the mosfet which acts as a wave generator to switch on and off for the mosfet....then ground of the mosfet also separated from the ic ground but the drain of the mosfet are using pcb to heavy wires then to transformer... i will take attach the pic along for you to see.....and 1 more prob which could not be solved...whcih the the waveform....i still cant get the desired waveform from cd 4001 and cd 4047.... i tried the cd 4047 output pin osc, pin Q and pin Q' all is the same in the datasheet...bt when connected to the cd 4001 it will become a square wave....which each of the output from the cd 4001 will have a phase different only not inverted waveform....when add together it will superimpose but not generating modified sine wave..... :'( :'( :'( at 1st, can generated the desired current and voltage but after awhile it will burn the CD4047 ic ...need help thanks
  9. dear au, about the grounding...can i separate the grounding as showed in the schematic.... i mean the mosfets has its own grounding and the ic's has it own groundin....or both mosfet and ic need to hav same grounding...i means is connected to same ground...just wan to confirm b4 i burns everything out... ;D ;D
  10. dear au, do i still need to add on the series resistor to the mosfet? or shouldnt i? thanks...if yes then i need to drill holes on my pcb board go lab to retry thanks
  11. dear Au, if the voltage from the mosfet is lower than the primary winding of the transformer for example....the voltage from the mosfet is approximately 5V then the rating of the transformer is 8V....will it have enough power to power the transformer? or it depends on the rating of the mosfet? can i put different grounding where the mosfets have different ground than ground together with the ic? becoz i afraid that the high current drain from the mosfet will affect the ic and burn it.... :-\ :-\ thanks for your precious opinion
  12. dear au, i have use the same connection which the updated by you...but still no avail, but i tried the cd4047 output from both pin 11, and and 10 and the output is inverted...but when fed into the CD4001...the output seems to be havin a square wave....how could this possible ? i still cant figure it what is wrong with the circuit....mayb is the frequency prob? and i also have taken out the resistor since is not needed.....and can i use the ceramic capacitor which has value of 221k? thanks for your reply
  13. dear au, then the 2 capacitors to be used is metalized plastic type? since there are no 0.22uF capacitors in the circuit. so 50Hz of frequency doesnt neccessary to put the resistor in front of the mosfet? since the osc frequency in this circuit is just 50Hz.... the capacitors and resistors used in the circuit is just a protection from the current of the transformer or just use for filtering purposes?
  14. hi au, this is means the capacitors can be used is ceramic type? i think without the resistors infront of the mosfet doesnt affect much if the circuit? y the capacitor and resistor near the transformer is reduced?
  15. dear all, i think i used the corrected connection for the cd4047 and cd 4001....but i still cant get the require modified sine wave form through it ...is the polarity of the capacitors used affects the result? i hav connected the polarity correctly and use the same value of caps and resistors....my mosfet as source follower? my mosfet in the circuit purposes is just used to drain the current from the batterty through the transformer to ground so that it will produces a positive voltage on the upper primary windings so do the lower part of the mosfet...if any misconnection pls let me know and any good recommendation for redesign the circuit and to make it works is highly appreciated.....thanks.... i reattach the diagram for u all to view....
  16. dear au, 1 more question....if the dc power supply used to power the inverter circuit which have maximum 3amperes....can it drive the transformer which have the rating of 8.5-0-8.5V? thanks
  17. dear Au, i have contruct the circuit and the waveform the oscilloscope is not the expected output i wanted. the output is not a modified square wave instead of square wave only. i attach the waveform for u to view.... can u pls give some opinion on this?? thanks
  18. hi au, i wan to ask u something....do the copper in the pcb board must have a thicker width? since the mosfet drain a quite high current... is about 16 amps....or double for modified sine wave? if it have thinner width will it affect the efficiency of the inverter? thanks again
  19. dear Au , i think i get what u mean if this is correct, the input and output of the transfomer is calculated using Vrms or so call average value? so in order to get the Vrms in the transfomer we need to 12V/square root 2 = 8.5V in the primary winding of the transfomer? so we can get the output of the transformer Vpeak value as 220Vac peak straight? or the output of the transformer still need to multiply by square root 2 since the output of the transformer is just the Vrms value not Vpeak? for the current part in the mosfet.....what u means is the mosfet in the inverter on each side is 15.7A drain from the battery so with the modified sine wave because of the mosfet turned off half of the time we need to double the current in the mosfet in order to get the average output power which is 150w continuos so the formula given to me which is 2 root 2 times 15.7A where the 2 in front is to double the current in the mosfet in order to get same avg output power....is this correct? but how we know by doing this we can get the same average output? can u explain more and also why their current need to be double to produce same avg output power for the turn off for half of time in the mosfet .... but i also need some article for my above question which i need to prove it in my thesis.....so my thesis is more solid... thanks Au
  20. dear Au, on what gound u state that i shold use the 8.5-0-8.5 to 220V to get the Vpeak for the output of the transformer? as i know output of the transformer is Vrms? u stated that in order to get Vpeak at the output , the value for the inverter the input of the transformer winding is calculated as 12/8.5 which is nearly square root 2...do u have any site or article to prove this? the vpeak at the output transfomer become Vpeak as sine wave if i use the 8.5-0-8.5V to 220V transformer? do u have any nice article about transformer? do u have any site or article on this? so i can understand more...because i dont know which formula you are using to calculate the current in mosfet....which is peak current is 2-root-2 times 15.7A=44.4A because there is pauses between the mosfet . as i know Ipeak =square root 2 multiply by Vrms.....by there is extra 2 in front? my theory on inverter is very limited hope you can giv me more information about it thanks
  21. dear au, i think i can use this mosfet rite? IRFZ48NPbF i will attach the datasheet for your reference....thanks
  22. hi au, can u pls gimme the link? i go and find myself :P thanks cos i need to create the inverter as small as i can
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