Building a custom notch filter

OK. The 60Hz port just seemed superfluous since it was that which you were trying to eliminate. It might also affect the depth of the notch.

The 60Hz filter will only remove 60Hz and leave the noise -- I thought it was the noise you were trying to measure?

Yes, but i want to analyse signal which has 60 Hz component and then once without the 60 Hz component

OK, that circuit (as far as I can tell) will only give you one or the other, but not a 60Hz + noise.

I'm not sure if you can combine the outputs again, but getting their relative levels correct would be an issue.

Thanks again steve, I can only say once i am done with it. But will keep your inputs in mind.

btw.. any idea what the VA rating of the power transformer could be ? the TX3 (60 hz port one) ? is it a low VA rating one ?

http://search.digikey.com/scripts/Dk...e=3FL230-50-ND

does this fit the bill ?

I can't really help you with the choice of transformer for that. The transformer you have selected would certainly work for 60Hz signals, but whether it has the right impedance and turns ratio is another question.

No, that's a 12VA 2x115V output. You don't want to apply that much into you USB 'scope..
Use the lowest power & lowest voltage you can find, certainly not much more than a 1VA 5V transformer.

oh thanks.. so i will this be good enough ?

http://trcelectronics.com/Tamura/pdf/3fdpsd-4.pdf
(3FDPSD-410) available here
http://search.digikey.com/scripts/Dk...ywords=3FD-410

This is the specs of the usb oscilloscope which will be connected

Maximum duration input voltage
5V/Div ~ 1V/Div: 50Vpk+DC
0 .5V/Div ~ 0.1V/Div: 20Vpk+DC
0.05V/Div ~ 0.01V/Div: 2Vpk+DC
http://www.armkits.com/product/DS2300.asp

That one will at least be safe for your 'scope but is still way more powerful (+ heavy & costly) than neccessary.
Use this (single primary) or this (dual primary).
Digikey doesn't say what the single primary voltage actually is, but the datasheet reveals it's 115V (surprise-surprise). Even if you're in a 115 country it won't matter if you get the dual primary and run this transformer at half voltage.
You'll have to be careful anyway to stay away from the lowest range on your 'scope. (5V x 1.1 x 1.24 x 1.414 = max 9.65Vpk)

ooh... thats great help... i was a little concerned too.
whats this deal with series & parallel output voltage ?

i'll be taking the voltage out on parallel ryt ? according to my circuit diagram specified on page 1. ( Transformer 3 - 60Hz port one )
esentially my parallel output voltage should be 5V ryt ?

and which would you recommend single or dual primary ?


Again.. thanks a lot......

Both have dual 5V secondaries that can be wired in series for 10V, used independently, or wired in parallell for 5V full power. You need only use one of the secondaries for your application.
With dual primaries you can wire them in series (for 230V use) if you want, but still apply 115V to it, resulting in only 2.5V output. This might also have the advantage of less waveform distortion since the core is nowhere near saturation. I'd get the dual primary just for the added flexibility. More pins to worry about but the same price.