Electronics Forum / Components / November 2003

Wow, what a contraption.  I thought toroids were wound by hand in some
Mexican sweatshop.  Well, maybe it's still a sweatshop, but now I know
that they don't have to be wound by hand..  ;-)
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2574825744&category

It's part of a design for a T/R sense circuit for a noise cancellation
device.
I won't bore you with too many details.  One thing I noticed in a
design I'm looking at is that 1W resistors could be subject to as much

Hi all, I am working on project that requires trig, algebra as well as basic
math functions. I am working with a Pic 16F84A, and I was wondering what type
of math coprocessor would be good to use with this MUC?
Thanks To all

Is there any chemical substance capable of completely dissolving
epoxy glass, 1.6 mm thick, but not dissolving at all the 35 uM
copper that coats it? (it's a photoetched printed circuit board)
I'm trying to find a cheap way for making stencils.

I'm looking for a 2.5V, 100MHz clock source, preferably in a surface
mount package.  Any part or supplier suggestions?
2.5V operation is my highest priority.  Existence of an Australian
supplier would also be helpful!

Does anybody know of a Canadian or US source for the TFDS4500 IR module
made by Vishay Telefunken? I have checked the usual sources, Mouser,
Newark, Digi-key and have come up empty. Any help would be appreciated.
Thanks

I'm looking for pinout data for 2N333, 2N336, and 2N324. All are stated as
being TO-5, a variant, AFAIK, of TO-92. All three of these are discontinued
numbers.
When I check NTEINC.com for a cross, I get NTE123A in a different package:

In an industrial application I need to monitor air flow and pressure/vacuum
in a dust collection system (it is just like a huge vacuum cleaner) to
understand if the filters are working okay or not.
Would any one have any experience in such an application to share or any

I'm looking for a modern replacement for the MC1496 Balanced
modulator/multiplier IC. I need a wider bandwidth  than the original~ 40MHz;
preferably with a SPICE model. Maybe a suitable transistor array would do.
I know about the NA602/612 devices.

I'm looking for a miniature (i.e. .5"=.75" diameter) rotary switch --
4-pole, 6-position, non-shorting.    Anyone know who might carry such an
item?  Thanks.
Joe

Looking for 78GKC voltage regulator circuits and data sheet.  Would
appreciate it if anyone could post or email me such, or point me to a
source.
Thanks,

This is a tough one. Can anyone help me out?
TIA
Ray
email: kansas_ray

There are a lot of different kinds of LED on the market these days.  I'm
trying to understand some of the distinctions.
I'm seeing some called "low-current" (e.g., Fairchild HLMP-D150).  They
don't seem to be any different than normal LEDs, except they're

lately I've had a lot of OLD equipment (I repair industrial Food
Equipment...some over 20 years old) that all use dual potentiometers.
Surprise, surprise.....these are becoming incredibly difficult to find.
Anyone have a source for a wide variety of values of dual pots?.

Where can I find data on japanese diodes and other Japanese devices? Transistors
are easy, just type 'japanese transistor data' on Google...
Any on-line cross-reference sites?
Getting replacements from NTE is near out of luck, as I am in Brazil.