To: rsgb_lf_group@blacksheep.org Date: Wed, 18 May 2005 14:43:52 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4807.1700 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4807.1700 X-SPF-Result: relay.thorcom.net: 64.97.168.34 is neither permitted nor denied by domain of virgin.net Subject: LF: cores Content-Type: text/html; charset=windows-1252 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Spam-Filtered: by PlusNet SpamCORE (v4.00s) Content-transfer-encoding: 8bit

Hi All

Another anomaly about these ferrite transformers. I wound a 3c type core with a Sec of 24 turns and measured it to be 1.38 mh then over wound this with the prim of 8 turns, this reduced the Sec to 982 uh with a prim of 110 uh. The ratio is about right x9 for a 1:3 ratio. I suppose meaurements should only be made when the transformer is complete with all windings, but it does show the effects of multiple windings over a single layer.

Except one has a lot of test equipment it seems most dabblers are working in the dark especially at LF, no wonder there are so many BANGS especially the FETS!!!!!!!1

To guarantee a robust no bang amplifier maybe TUBES are still the best bet.

From messages received it appears to be that as long as the ratio Prim /Sec is correct the ferrite material is not important but then why such a variety of different core material, although I do realise that certain other ccts at HF work better with a particular core mix.

I could do with some design literature written by others that have experience in the ferrite transformer research field.

73 de Mal/G3KEV