[Amps] What is it called?

[David Kirkby]

Ian White, G3SEK wrote:

>
> Tufnol is a machinable grade of plain old-fashioned phenolic (Brit: 
> paxolin).
>
> The big UK electronics distributors like RS Components and Farnell are 
> incredibly expensive for engineering materials - you should see what 
> they charge for that extra "i" in aluminium. 

RS is not cheap. You do pay for their excellent service, which is useful 
professionally, but not necessarily for amateur use. They have data 
sheets for most products (including these Tufnols) online, although you 
have to register to get data sheets. If they don't have the data 
on-line, they FAX it to you. If there is a problem, they sort it out 
quickly on the phone. I've never had a problem that is not resolved the 
same day. Yet I have used them for nearly 20 years professionally.

I find I can place an order with RS up to about 4pm and without paying 
for any extra delivery and can be 99% sure their first class post will 
get it to me the next day. In London at least, their delivery is very fast.

Farnell do a *guaranteed* next day delivery for zero cost, with no 
minimum order. I doubt they would do the same for a one-off amateur 
purchase on a credit card, but professionally I find both RS and Farnell 
good, and use them a lot.

Recently some storage draws were delivered to work and the courier hit 
them hard on the floor, bending the sides. I phoned up RS and within two 
hours there was another one delivered. RS's prices must reflect this.

I've looked at the prices of some hard disks in RS and laugh at them. 
They are totally OTT, but then when I had a  SCSI CD-writer fail that I 
personally purchased from 'Dabs' it took me weeks to get a returns 
number. Dabs is cheap, but their service ****.

What price/service you can tolerate professionally is usually very 
different from what you can tolerate for hobbies, but I would agree with 
Ian that they might not have been the best source for these materials. 
It is just one source I know.


PS, for amateur us, Maxim
http://www.maxim-ic.com/
have a very good policy on samples for ICs - shame they don't do 
engineering materials.  You can get several of any of their ICs sent as 
samples by courier for zero cost.

PPS
I know a colleague, who lists on his web site a hobby of 'Finding things 
for free'

http://www.medphys.ucl.ac.uk/~mefry/

wanted Texas Instruments DSP chips. He used to buy DSP evaluation kits, 
remove the DSPs, then throw the rest of the board in the bin. This was 
cheaper than to buy the DSP chips at commerical prices. This was many 
years ago, but shows with a bit of ingenuity you can save money. Texas 
Instruments sell the DSP evaluation kits at a loss I am sure. For any 
academics, you probably know TI will give them away if you ask nicely.

I use an expensive data acquisition board professionally with an ADC 
that samples at 200MS/s. Guess what DSP it uses - TI of course. Texas 
Instruments might make a loss on the evaluation boards, but they reap 
the benefits when people use these things professionally.