fm transmitter help

[Voodoo Child]

i am trying to build this all from parts from radioshack

http://www.uoguelph.ca/~antoon/circ/fmt2.htm

1st question, are the resistors 1/2 watt of 1/4 watt?

2nd question, the
C2 = 4-40pF capactior, I read somewhere that that was a trimmer, or something, basically
what i am asking is, what radioshack part number will suffice for that?

and for this thing, will i be able, if i am in the car, someone is listening to something on the radio, could i override what they are listening to
with my mp3 player and this baby?


and on the guide, it says something like no using electrolitic caps or something.

the only 4.7uf one i can find is the kind i cant use, could i say screw it and use it anyway? could i not use it? could i use a subsitute? could i get a differnt capacitor?


i am really siked for this, spelled that wrong, here is my cart

http://www.radioshack.com/cart/index.jsp?clickid=topnav_cart_txt

6 something dollars? not bad!

when u hit on the link, it may say nothing in cart, so ill tellu what i got in there.

i got the 2 resistors, transistor, 4.7 electrolitic cap thing , .001uf cap, and a 2AA battery holder that has a 9v snap on the top. for 6.74

 

[~K-Pow~]

That's a neat project i see there. I'm sorry i can't help you though, but i'd like to know how it turns out.

 

[root]

weird..
I looked all over the radio shack website and couldn't find a single variable cap,


these are what you want...
http://www.maplin.co.uk/search.aspx...omMenu=y&criteria=Variable&doy=10m5&worldid=3

0.1uf caps
http://www.radioshack.com/product/i...Metal+Film+Capacitors&fbc=1&parentPage=family

0.01uf cap
http://www.radioshack.com/product/i...Metal+Film+Capacitors&fbc=1&parentPage=family

there is no 4.7uf, it's 4.f pf (pico farrad not microfarrad)
but again good ole radioshack don't seem to sell one...

how on earth they still justify the title RADIO shack without selling radio parts?

 

[Voodoo Child]

i have desided to go with this one

http://www.uoguelph.ca/~antoon/circ/fmt2.htm

 

[Voodoo Child]

weird..
I looked all over the radio shack website and couldn't find a single variable cap,


these are what you want...
http://www.maplin.co.uk/search.aspx?MenuNo=1584&MenuName=Variable&FromMenu=y&criteria=Variable&doy=10m5&worldid=3

0.1uf caps
http://www.radioshack.com/product/index.jsp?productId=2102589&cp=2032058.2032230.2032267&allCount=102&fbn=Type%2FMetal+Film+Capacitors&f=PAD%2FProduct+Type%2FMetal+Film+Capacitors&fbc=1&parentPage=family

0.01uf cap
http://www.radioshack.com/product/index.jsp?productId=2103628&cp=2032058.2032230.2032267&allCount=102&fbn=Type%2FMetal+Film+Capacitors&f=PAD%2FProduct+Type%2FMetal+Film+Capacitors&fbc=1&parentPage=family

there is no 4.7uf, it's 4.f pf (pico farrad not microfarrad)
but again good ole radioshack don't seem to sell one...

how on earth they still justify the title RADIO shack without selling radio parts?

there are trimmers at radioshack.com

and wait, will it not work if i have a 4.7uf?

 

[root]

there are trimmers at radioshack.com

and wait, will it not work if i have a 4.7uf?

really?

All I see it rtimmer pots, not trimmer caps.

I was unable to find tunning capacitors, (variable capacitors trimmer caps) at all anywhere on the site... (did you find any? prehaps you have to actully go into the shop).

no, it won't work, if you have a 4.7uF capacitor,
it's a tunned circuit,
a 4.7uf capacitor is in the order of a million times greaner value than a 4.7pf capacitor.

f = farad = x10^1
mf = milli farad = x10^-3
uf = microfarad = x10^-6
nf = nanofarad = x10^-9
pf = picofarad = x10^-12

 

[Voodoo Child]

no what if i got a ultra small uf cap?

and o wait these are resistor caps.

 

[root]

even if you got a very small (e.g. 0.001 uF cap, it's still be almost 10,000 times too big.

do Radioshack stores have a components counter if you actually go into them, you might be better actually trying to walk into a store with a parts list.


either that..
or you could just change supplier
trimmer cap - (5pf - 40pf) http://www.alliedelec.com/Search/Pr...=602&MPN=CTZ3E-40C-W1-PF&DESC=CTZ3E-40C-W1-PF

capacitor (4.7pf) http://www.alliedelec.com/Search/SearchResults.asp?SearchQuery=4.7pf

that place seems a little cheaper than Radio shack as well...

 

[Voodoo Child]

i have heard digikey and mouser are really good, i dont know bout allied electronics. but i don't want to order like 2 things and pay 5 dollar shipping, i would want to buy everything off of that site. and, idk, maybe i am intimidated, but when u search for something, there is like 100 results of the same thing, so i dont know, i may just say screw this whole thing.

 

[root]

(you could always order all the parts from one site?)

if there are loads just pick the first thing off the list. or the part that best sounds like the one you want. or just the cheapest part!

as a piece of advice, 4 band metalized resitors are the most accurate, (and most expensive), the regular 1/4Watt clay resistors would probably be fine.

ceramic capacitors are the least accurate (have the least tollerance),
Eecrolytic capacitors are polarised (and the circuit specifically says not to use them,
metalized and tamtlyium capacitors are the most accurate, best quality, and again most expensive, I would imagine that ceramic capacitors would be fine for this circuit however...

I'm not american, so I can't offer any advice on the best places in america to buy components.