| TRANZYSTOROWY WZMACNIACZ KF 4X MRF150 |
| Link do strony podajacej informacjie o EB104 i zastosowanych SD2933 zamiast MRF150. http://eb104.unoforum.ru/?1-16-0-00000001-000-0-0 RU konkurent CCI LINK http://eb104.ru/internet-magazin/komponenty-dlya-sborki-eb104/page-2 SD2933 na ebay tu: http://www.ebay.co.uk/sch/ian.turkentine/m.html?item=251987084629&hash=item3aab99c555&pt=LH_DefaultDomain_3&rt=nc&_trksid=p2047675.l2562 P.S. Wazne informacje dla tych ,ktorzy zdecydowali sie na wykorzystanie SD2933 zamiast MRF150. Pytanie K9VF Hello Everyone, Victor (UA3QLC) gave me a link to this forum with information about using SD2933 MOSFETs with the EB104 board. I'm in the process of laying out a PCB similar to EB104 but with more room for the SD2933. After seeing Victor's project I'm not sure a larger board is needed, but I do enjoy etching my own PCB when possible using toner transfer methods. I have a couple of questions if I may ask. #1. I see the input transformer T1 is increased from 3 turns to 4 turns for better matching of SD2933 input. That confirms my input calculations also that a 1:16 ratio is better suited for the input. What about C2 capacitor? Is the same 820 pF size used? #2. How about output transformer T3 - is it the same 3 turns used for a 9:1 ratio transformer? What about C11 - any changes from the 1200 pF on EB104 circuit? #3. Is T3 the same size using SD2933 for 900 watts output? The same #43 mix Ferrite core? Is the length about 2.54 CM? or longer? Thank you all again for any help, 73 de Ken H. K9FV- Odpowiedz Victor UA3QLC Hi, Ken! Nice to meet you here. The answers are as follows: 1)Yes, your eyes are sharp enough to find one additional turn for 1:16 ratio, because of more input capacitance of SD2933. C2 remains original, 820 pF. 2)T3 has 9:1 ratio, but C11 has changed to 820 pF. It is hard to find the silver mica capacitors here. ( Mnie udalo sie kupic kondensatory w SP , chip capacitors 680pF/3kV ,MALY ESR , KOMENTARZ SP6FPH ) We tried old russian mica capasitor, but it is getting hot too fast. To increase the VAR capacity we will replace them by MuRata ceramic chip capacitors 100 pf 3 KV (model GRM42A7U3F101JW31L , like in PW-1 by ICOM) in parallel . 3)The size of T3 seems to be enough for this power. We tested this construction on the table with the full power for more than 10 minutes without air cooling, checking the temp by fingertips but C11 and R19/20 only were hot. Bardzo wazna, infprmacja patrz nazdjecia (komentarz sp6fph) CZERWONA STRZAKA WSKAZUJE PUNKT W KTORYM PCB PODLACZONE JEST Z PLASKOWNIKIEM MIEDZIANYM PIN3 i PIN4 (SOURCE ) SD2933 nie sa przylutowane do PCB . Wystarczy mechaniczne polaczenie tranzyctora do miedzi. I could make advise for your own PCB make shure that RF current will flow through the copper plate,, not through PCB. The brass screws are enough to obtain the contact between transistor and copper. |