Continuation of "TOKO Inductors Needed for EM Theremin"

This post was a mistake, my browser loaded the previous one twice, and I can't delete it :(

therm13--I didn't catch this thread earlier, when you asked about antennae; but you can see what I used at

http://www.abarbour.net/tmax.html

The lock washers I put on the inside of the unions were unnecessary (and when released tended to drop metal shavings into the cabinet). One plain washer on the inside of the cabinet, underneath the nut, works fine. (Note: my cabinet is wooden.)

Looks like a really nice set of antennas!

I think that I'm going to do just one bend to form a single straight 'U' loop.

I plan to make my cabinet out of wood too, so I'll just stick with regular washers.

Did you fill the antenna pipe with something to add stiffness and strength?

Thanks,
Dan

Thanks; no filling--they are quite strong and light.

I've looked at some images of the LM178L12 and LM179L12 on the web, and they appear to be a three-lead IC. However, the components that I got for the DC regulation are 8 pin ICs. Is this even the correct component. The pins are voltage in, voltage out, four grounds, and two "NC" pins. What does the "NC" stand for, and what do they do? Why would there be four ground pins? Should I ignore the "NC" pins, randomly pick a ground, and use the input and output as normal?

Images:
What I have: http://www.national.com/images/pf/LM78L12/00774402.jpg

What it seems like is used in the plans (three pins): http://ic.chinadz.com/images/pic/L/LM/LM78L12_QX.JPG

Thanks,
Dan

You ordered the wrong package. If it does not cost you anything to return them for the TO92 package I would return them. If you have to
pay postage or a handling fee then I would
keep them.

The three terminal device is easier to wire but the 8 pin DIP should work fine in this low current application. Wire all of the grounds together.

NC means No Connect. To do not solder anything to these pins.

(* jcl *)

The other three lead package for -12V at Newark is actually out of stock, so I guess I'll have to use the ones I have. Why would this setup of the IC be worse for higher current applications?

There are two ground pins on each side of the IC, so should I just treat all of them as one pin, even though they're on different sides?

One more thing ---

Everytime I get an email that contains "TOKO Inductors" in the subject this gmail ad pops up ---

TOKO Coils & Inductors - www.bec.co.uk -
BEC is a U.K Distributor of Toko Coils, Filters and Inductors

This probably doesn't help us in the U.S. but maybe someone in the UK or Europe will find it useful.

(* jcl *)

[b]The other three lead package for -12V at Newark is actually out of stock, so I guess I'll have to use the ones I have. Why would this setup of the IC be worse for higher current applications?[/b]

It is more difficult to heatsink the DIP package
compared to a TO92 or TO220. Also the thermal resistance of the DIP is probably higher.
I haven't calculated the temperature rise in
this application but I would be surprised if any
of the packages would be a problem (without a
heatsink).

Since you have the National Semi Application
notes you could calculate the temperature rise ;-) You would definitely get some bonus points in
your project report.

(* jcl *)

Could the version at the following location work for positive 12V?

http://www.mouser.com/search/productdetail.aspx?R=MC78L12ACPvirtualkey51210000
virtualkey512-MC78L12ACP


How about the -12V counterpart?

http://www.mouser.com/search/productdetail.aspx?R=MC79L12ACPvirtualkey51210000
virtualkey512-MC79L12ACP


-Dan