This is a heavy duty design of a Pulse Width Modulator DC/AC inverter using the chip SG35! "#$ve %een using it as a %ac&up to po'er up all (y house 'hen outages occur since apro)" * years non stop"#f you li&e the 'or& and intend to %uild the circuit don$t forget to clic& on the +follo'+ %utton so #&no' ho' (any people %enefit fro( the design, Than&s"Notes:1> The sche(atic circuit design is for a 5- 'att output, 'hile the pics are of (y .5-- 'atts inverter that i %uilt, to increase the po'er of the circuit you have to add (ore of the /0 and /1 transistors in parallel, each pair you add 'ill increase your po'er %y 5- 'atts, e)2 to get 05- 'atts of po'er fro( the inverter you need to add in parallelof /0 andof /1 to the original design"2> #f you increase the po'er transistors you have to enlarge the T transfor(er to (atch the ne'needs, the circuit$s transfor(er is rated 5 a(ps to handle 5- 'atts of -v, for every . additional a(p you need on the -v side you have to increase .- a(ps on the .v side, of course there are li(its to the thic&ness of the 'inding so if you need (ore than 05- 'atts i reco((end that you use a !3DC supply instead of . volts2DC voltage and Transformer "T2" winding recommendation:Power Supply Winding05-' .3DC P2!3 +.4-4.+ / S2-3.5--' !3DC P2!13 +!4-4!+ / S2-35-' 3*3DC P203 +3*4-43*+ / S2-33---' !13DC P25*3 +!14-4!1+ / S2-3305-' *-3DC P2.-3 +*-4-4*-+ / S2-3!5--' 03DC P2.!!3 +04-40+ / S2-355-' 1!3DC P2.*13 +1!4-41!+ / S2-3*The transfor(er should %e +center tapped+ at the pri(ary side"**6ou can (a&e the secondary ..-v if needed"***The transfor(er in the pic is a custo( (ade 7!13 center tapped / -v 8 --- 'atts, 'eights li&e .- &ilos"3> 9. is to set the PWM duty cycle to -v" Connect volt(eter to the output of your inverter andvary 39. till the voltage reads -3"4> 9 is to set the fre:uency to 5- or *- ;< 79 range is %et'een !-;< to 05; The design does not include a %attery charger since each person 'ill %e %uilding a custo( version of the inverter 'ith specific po'er needs" #f you are ordering a custo( (ade transfor(er you can as& the( to ta&e out for you an additional output 'ire on the pri(ary side to give .!v 7%et'een point - and this ne' 'ire8 and use it to charge a .v %attery, of course this needs a seperate circuit to control charging auto cut4off" Aut any'ay this is not advisa%le %ecause it 'ill shorten the life of the transfor(er itself since using it as a charger 'ill toast the ena(el coating layer of the copper 'ires over ti(e" Any'ay "" 6CS can %e done to reduce cost""> A cooling fan 'ill %e needed to reduce heat off the heat sin&s and transfor(er, i reco((end getting a -v fan and connecting it to the output T transfor(er, 'hen you po'er up the circuit the fan 'ill start this 'ill al'ays give you a si(ple 'ay to &no' that -v is present and everything is D@"" 6ou can use a co(puter$s old po'er supply fan if you li&e"Eote that the fan (ust suc& air out fro( the inverter case and EDT %lo' inside, so install it the correct 'ay or it 'ill %e useless"Also note ho' # fi)ed %oth the heat sin&s and 'here the fan is, in a 'ay that the fan suc&s hot air fro( li&e a channel %et'een theheatsin&s" 1#>circuit %rea&ers are reco((ended instead of fuses, one on the DC side and one on the AC side, depending on your designC)2 for a !vDC 7 .5-- 'atts design 8 put a *-A(p %rea&er on the DC side and a *A(p on the AC side">or every .a(p of -vAC you 'ill %e draining li&e 1 to .- A(ps fro( the .v %attery, (a&e your calculations F11> The;eat sin&s should %e %ig enough to cool the transistors, they are separate and should EDT touch each other" +see the pics+12> #m$ortant: #f you$re %uilding a %ig design that uses (ore than !3DC as po'er source, (a&e sure not to supply the driver circuit 'ith (ore than !v (a)i(u(" 7CG2 #f you have ! %atteries !). ? !1v , connect the vH supply of the driver circuit to the second %attery$s 7H8 ter(inal 'ith a thin . (( 'ire 'hich is (ore than enough" this supplies the driver circuit 'ith H!v 'hile supplies the po'er transfor(er 'ith H!1v8 +see the %atteries pic e)a(ple+13> +Dptional+ 2 Deep Cycle %atteries are your %est choice, consider the( for %est results "" read (ore14> Ae cautious 'hen %uilding this circuit it involves high voltage 'hich is lethal, any part you touch 'hen the circuit is DE could give you a nasty painful Iolt, specially the heat4sin&s, never touch the( 'hen the circuit is on to see if the transistors are hot FF # ate it several ti(es 2815> The optional +Jo' voltage 'arning+ is already e(%edded in the PCA layout, you can disregard it and not install it$s co(ponents if you do not need it" #t does not affect the functionality of the (ain circuit"16> The Motorola E*00 is a dura%le heavy duty po'er transistor, it is used in (any BS tan&s for it$s relia%ility %ut unfortunately it is a very hard to find part, instead you can su%stitute each E*00 'ith) E3003 or any e:uivalent"1> #$ve included an optional +Aattery level indicator+ circuit diagra( that has ! JCDs, you can see it installed on the front panel of (y inverter pic, it is functioning great and sho's precisely ho' (uch Iuice the %atteries still have" # have included a s(all relay that is po'ered %y the last JCD to auto shutoff the inverter once last JCD is off"1!> Also included an optional +Dverload circuit+, it is very easy to %uild and can %e cali%rated to the desired overload current threshold cutoff point through the potentio(eter 39."9. is rated 5'atts for inverters upto .--- 'atts" >or %igger versions of the inverter li&e .--- to 3--- 'atts inverters, replace 9. 7. oh(, 5'atts8 'ith 7. oh(, .0'atts8 'hich should handle loads upto .- 3A"Ma&e sure you install a proper relay to handle %ig current drains"1"> %lease g&'s ta(e 'o&r time to read and &nderstand m' notes) *rowse and read t+e $osts and ,&estions as(ed *' ot+ers *eca&se t+ere are man' &sef&l information listed in re$lies- T+e main reason for me not answering 'o&r ,&estion is *eca&se it +as alread' *een as(ed *efore and answered &$on-2#> .t wo&ld *e nice and ins$iring for ot+ers if 'o& ta(e some $+otos and s+ow &s +ow 'o& *&ilt 'o&r version) an' additions to t+e circ&it are mostl' welcomed to *e listed +ere) we can all *enefit from t+em-21> %lease clic( on t+e "./ve made it" *&tton0icon if 'o& did *&ild t+e circ&it so . (now +owman' $eo$le *enefit from t+is design-22> Testing 'o&r com$leted circ&it wit+ crocodile cli$s or t+in wires 1.22 N3T 1345 6 7o&/ll get wrong voltage readings-