Re: Carbon Composition Resistors
- From: Ian Jackson <IanJacksonRemoveThisBit@xxxxxxxxxxxxxxxxx>
- Date: Mon, 16 Apr 2007 17:53:08 +0100
In message <%iNUh.18071$5S7.9910@xxxxxxxxxxxx>, JM <johnny@xxxxxxxxxx> writes
frequency is another question.
Thanks to all for the replies. I thought that APC had to be carbon
composition types precisely because of the inductive effect of the
spiral in carbon film types which as I intend to use on a 70MHz valve
PA could be critical, was just going to wind one turn around each.
I'll continue my search but if I get no luck then maybe 15 Ohms may
work so if it is OK with you, Johnny, I'll get back to you later.
Thanks again,
David
Yes that's ok David.
I was not sure what freq you were wanting them for.
I remember that with the G2DAF APC they were 5 or 6 turns
if memory serves.
That was 160 to 10.
But just let me know
de Johnny G3LIV
I've always understood that the purpose of using a resistor as a coil former on which to wind an anti-parasitic choke is to make the inductor lossy, thus preventing any tendency to oscillate by dissipating energy at VHF/UHF. The actual resistor value is probably non-critical, and 47 ohms may essentially a 'traditional' value. 15 ohms will probably be fine. I also doubt if it matters that the resistor itself is somewhat inductive. I think '2W carbon' was often specified mainly because the size was right, and most resistors were carbon anyway!
Ian.
--
.
- References:
- Carbon Composition Resistors
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- Re: Carbon Composition Resistors
- From: Steve
- Re: Carbon Composition Resistors
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- Carbon Composition Resistors
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