Longitudinal wave research

[Jdo300]

Hi Mark,

Count me in on that one. I was just talking to Hank and derek about these. They would be the perfect solution but I can't afford to pay $40+ per chip if I only buy three of them. Where did you look to get the price you mentioned?

God Bless,
Jason O

[MarkSnoswell]

@Rob

Measuring Q ...
Measure the peak amplitude,pA at resonance F.
Measure the high and low frequencies where the amplitude is exactly pA/2
The difference in the half height frequencies = dF
Q = F/dF

WIth Q's in the 1000's you need very accurate equipment. I am borrowing a HP 33120, 15 Mhz arbituary waveform generator for these test.
Peak amplitudes are measured with the absolute voltage cursor on my Tektronics TAS 475 scope.
After determining the resonant frequency, F, and peak amplitude, pA, I set the amplitude cursor to pA/2 and find the low and high frequencies with exactly pA/2 peak amplitude.

With the equipment I have the resonant frequencies are accurate to +-0.05% and the amplitude to +-1%
The amplitude error leads to increacing errors when determining high Q's. With Q's in the 1000's my error is probably +-20% or so.

[MeggerMan]

Hi Jason,
These are SOIC by the way, so as long as people realise these are fairly small devices (1.5mm pin pitch) but not too bad.
Cheapest price is off the Maxim shop site:
https://shop.maxim-ic.com/storefront/viewpriceavailable.do
Then search for:
DS1023S-100+

http://datasheets.maxim-ic.com/en/ds/DS1023-DS1023S.pdf

Price breaks:
1-24    $ 9.87
25-99     $ 8.11   
100-499   $ 7.36   
500-999   $ 7.36
1000+     $ 7.22

So I'm suggesting we get someone in the States to order them and post them out to the various countries as samples to avoid the import duties.

I can take 10  off. 
It may be that someone can work out a way using OR/AND gates to use just one for 3 or 4 coils.

Regards
Rob

[Thaelin]

   Wonder what they would do if I walked in their front door and wanted to buy a few?   About 3 miles from them.   

thaelin

[MeggerMan]

Hi Thaelin,
Give them a call and see if you can collect as it will save on courier charges.
I have emailed datadelay.com about a quote for the 3D7622 device: 10nsÃ,  to 4ms in 1ns steps .
http://www.datadelay.com/datasheets/3d7622.pdf

I will contact Maxim UK and see what price they can offer but I doubt it will beat the price of about 8 USD each.

The 3D7622 is the ultimate device, so I would prefer this over the maxim device, even if its twice the price.

[Edit 17thSept'07]
Hmm, I was right, they are more than twice the price:
Price breaks:
1 -49 24.14 GBP each
50 -99 17.77 GBP each
100+ 15.35 GBP each
Prices include VAT

12.50 GBP postage

Price was from: http://uk.nuhorizons.com/
Minimum order is 50 GBP so I would need to order 3 off.
Maybe Datadelay can give a better price.
Regards
Rob