Magnum I II (VLF) semiconductors

[baht7]

Thxs porkluvr

When I see 2 different ICs in a circuit with the same cross specs, especially CMOS, I ask questions.

Thanks for the explanations on the CA3130/3140.

Ill not use NTE 7144 in both slots.

onto the LF357 quest.

[porkluvr]

Have you tried Ebay? Aren't you in Thailand or do I have you mixed up with somebody else? I'll bet you there is somebody in your part of the world with some CA3130 for sale.

5 ea. for $5.99?

http://www.ebay.com/sch/i.html?_nkw=....c0.m270.l1313

[baht7]

Porklovr

Quest completed !!!! Hurrayyyyy

Now, wonderful job on the ca3130/3140........

2N3819 JFET?

Once again NTE has chosen a caddillac replacement (NTE-312).
I scanned a lot data sheets looking for an easier to find JFET.
While Gv,Ig,Id and NF are still active in my mind, the Transconductance and Freq are different between the 2N3812 verses the NTE312, being the NTE has a higher conductance @400Mhz.
The 2N3819 is ranged around 100Mhz.

Metal Detectors are a new creature for me, so I have to ask alot about the parts verses sensibility, stability, accuracey and repeatability.

Drifted off...

2N3819 alternate.
Any suggestions?

[baht7]

Yes, Im the Guy in Thailand

[porkluvr]

You keep asking these hard question?

I always thought that 2N3819 was the most common JFET on Earth but maybe that only goes for this half of the planet.

Your NTE312 should probably work fine.

[satdaveuk]

Good question!
I am struggling also with CA3130 and CA3140 in many designs i plan to do!

There still around, a company called VC Technology have 1,454 of each of those in stock at $7.50 each, larger orders proberly cheaper the company is based in Florida, i got that on a quick google search and that was almost top of the 1st page

[baht7]

hard questions !!!! hahahahahahah U wrote a book review on the CA3130/40 verses the NTE7144.

Had to press my luck..lol
ok..Ill just order a few NTE312s for the hell of it.