Hi all, I need this type of transfo, as shown here: http://www.electronics-lab.com/projects/power/033/index.html what transfo should i sear for ? they're not classified by the same way as "12-0-12" etc... please advise Thanks !
ummm, can i use a transfo that is meant to change 220 into 12 and 24 v ? that way i have 12-0-12, no ?
That type of transformer is commonly known as 'center-tapped' and usually abbreviated as 24VCT. The current rating is usually specified for the secondary windings, so according to the link you posted you will need at least 20A... That is one big transformer. [edit] Oops... I typed the wrong value earlier, for each side to be 12V you need 24VCT. I fixed my mistake above (was 12VCT). Also, I wonder if that is perhaps some kind of hand-wound inductor... Many of the car inverters I have seen for sale are not that large and heavy, I think they use some type of toroidal transformer/inductor? Then again, most are cheap and I doubt they live up to their lofty specifications.
thanks. I've found this one, but the power is rated by VA, how can i know how much VA i need ? 120VA, 0230V, 50/60Hz, 2 x 012V, Nuvotemtalema. http://www.radiospares.fr/cgi-bin/b...idehmkdfcefeceefdffhdfin.0&cacheID=f1netscape
waaah... thanks for helping, but ill probably buy one components list got to around 80EUR.... 8x10W resists are expensive, 10x2N3055 are expensive and transfo is also expensive.... apart from that, a bought one is guarenteed to work thanks again !
I must confess that I do not have a complete understanding of power conversion, so what follows is a simple description and I welcome anyone to make corrections or elaborate further. Basically, VA or Volt-Amps is a measure of power capability calulated by multiplying peak voltage * amp current. While this is also the formula for determing watts, the reactive nature of inductors and capacitance have an effect on the power used or generated. Short answer, you need a transformer with a VA rating at least equal to the power you want to transfer, and likely 50% more... so figure about 500VA to 750VA. Like I said, a big transformer. [edit] I was going to suggest that purchasing one might be a better alternative, but I didn't want to dampen your creative spirit
You'll also need a big heatsink or two for the power transistors, possibly the biggest expense of all. Maybe fan-cooled. A 12v battery-to-mains inverter is certainly much cheaper to buy than to build at that sort of wattage. Also there doesn't seem to be any attempt to produce a sine-wave output, the design could be bad for some mains-operated equipment.
