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Does anyone know where I could get a good circuit for an...

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thebigbasicq

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Ok, I'm a little confused about the drain coil. Will the...

drain coil be present if i attach the variable tuning capacitor as well? If the variable tuning capacitor is present then what should I do about the drain coil? What will come in it's place?

Thanx, the page is great!
 

thebigbasicq

New Member
Also I was wondering that should I remove the insulation of

the enameled copper wire if I have to make the drain coil? What about the source coil? Should I remove it's insulation as well?

Thanx
 

Gene

New Member
Regarding the varible cap and the 2 coils - all 3 components are required.

You do not remove the enamel insulation - it is needed. The ENDS of each wire and the 'tap' location WILL need to be cleaned in order to make the solder joint. I usually hold the END of the wire over a match flame for a second or two. This will turn the enamel insulation black. Then, carefully scrape the black (chared enamel) away with a sharp knife. Practice on a scrap of wire a few times before you wind your coils. Look carefully at the photos and you will see the silver colored wire (in place of the gold color) on the ends of the wire.

Good Luck!
 

thebigbasicq

New Member
I also found 1 anomaly in the description...

During description of each of the items there is a description about the magnet wires with the price. In this the author says that I will require a 26 guage and 30 guage wire for the project. While during the description of the preparation of source coil it says I require a 30guage wire while the drain coil it says I require a 22 guage wire. What guage wire should I use for which coil? Also which is the L1 coil and L2 coil? The project says nothing about it???

Thanx :?: :?: :?:
 

Pilot

New Member
L1 = Drain coil. D on the MPF102

L2 = Source coil. S on the MPF102

Looking at the picture I'd say he used 18 & 30awg
 

thebigbasicq

New Member
Also, there is no mention about the capacity of the variable

tuning capacitor. Which capacity should I try? What is the technical term used for it(for calling the capacitor i.e. is it just called a tuning capacitor or something else as well?). I have asked around in many shops all they have is a variable capacitor(the one with 3 legs 2 to 22pF) and not a tuning capacitor with the 6 pins.

Also, the MPF102 FET transistor was quite costly!
 

Gene

New Member
Sorry you got "ripped off" on your MPF102. Local price is 26 cents US.

http://www.jameco.com/cgi-bin/ncomm...earchResult.d2w/report?sort=BKW&search=MPF102


The word 'variable capacitor' and tuning capacitor' should be interchangeable for your application. The number of contacts are dependent on manufacturer's design and number of gangs/sections in the design. This little circuit is so specialized that I would try to get the variable (tuning) capacitor the author recommended.
 
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