PTCs from Farnell - group buy

bugbrand

I'm going to be placing a Farnell order at the end of this week, so if anyone would like to chip in getting some of the 1k axial PTC resistors
These are the small body ones, slightly cheaper than these other ones

Ref - this recent thread

RESISTOR, TEMP SENSING 1K

* Resistor element type:Temperature Sensing
* Resistance:1kR
* Case style:Axial
* Diameter, body:1.7mm
* Dissipation constant:5mW/°C
* Length / Height, external:3.2mm
* Length, lead:30mm
* Power rating:0.17W
* Ratio, resistance +:1.37%
* Resistance, insulation:10GR
* Stability, load life +:100 hours@125/C, 0.5
* Temp, op. max:125°C
* Temp, op. min:-40°C
* Temp. coeff, +:3000ppm/°C
* Time, response:3s
* Tolerance, +:5%
* Tolerance, -:5%
* Tolerance, temp coeff +:10%
* Tolerance, temp coeff -:10%

Quantity Price
1 - 24 £0.94
25 - 99 £0.76
100 - 249 £0.74
250 - 999 £0.54
1000 + £0.51

I know Fonik is interested and Para too. So we'll def. be at the £0.76 price - the more people who join, the cheaper it becomes.

Final price will be unit cost (inc VAT if applicable) plus shipping from UK.
Payment by Paypal once I've got the PTCs

And if anyone else has particular other things they'd like from farnell them do shout too..
EG:
Vactrols - NSL32 NSL32SR3
CA3046
Oh they still have CA3080E

Close of orders -- midday (UK time) Friday 9th March 2007

v-un-v · Posted: Mon Mar 05, 2007 4:11 am Post subject:

count me in for a few Very Happy

fonik · Posted: Mon Mar 05, 2007 5:57 am Post subject:

i'll take 30 pcs. (lifetime stock for me, i hope)

Coriolis · Joined: Apr 11, 2005 Posts: 616 Location: Stilling, Denmark

Great initiative!

I'll take 10-15, depending on shipping price to Denmark (how will you ship it?)
I'll just take a look to see if I need anything else...

C

bugbrand · Posted: Mon Mar 05, 2007 7:04 am Post subject:

Thanks!

Tom V-un-V - how many is a few?

Coriolis - ///shipping///
I'll send them out in small envelopes, with the resistors in a baggy wrapped in a little bubblewrap. The weight will be very little - certainly under 100g.

So shipping should be roughly:
UK - £0.50
Euro - £1.30
RoW - £2.40

Coriolis · Joined: Apr 11, 2005 Posts: 616 Location: Stilling, Denmark

Totally reasonable!!!!

Cool

Will let you know about any other stuff...

C

para · Joined: Oct 16, 2006 Posts: 276

yes yes, Bugs thanks for doing this!

quick question so i know how many. it was said that to use these 1k's on the XR-VCO you just half the input resistors right? but all of them, being all the tune controls and 1/v in, everything, just drop them to 50k and make the fine control a 1M65ish or something close.

that said, can i just do the same thing with my SN-voices then?

will the 1k’s not work in series for other things that may come across?

if all this is true then lets say -

30 - ptc

40 - ca3080e

30 - NSL32

10 - NSL32SR3

what are you using the ca3046 in? i'm not familiar with it yet. is it just because of the diff-pair in it and that you can use it all discrete so its easy to work with or what? i might have to grab a few just to have around.

if you need someone to order a few more to get another price break on something let me know.

thanks again,
steven

fonik · Posted: Mon Mar 05, 2007 7:38 am Post subject:

para · Joined: Oct 16, 2006 Posts: 276

thanks fonik but maybe i'm missing something? lets say i'm looking to get 2k - 3500ppm with two of these 1k's in series. it looks like that sheet just explains how to lower the temp control? do you mean that i should use 2 of the 1ks and then add a 3rd to drop the total ppm to the desired amount?

not that great at math these days and it doesn't actually say how much the average resistor will have except that 60R is about 50 ppm - when working with the 1k's which is odd to me?

so if i did my math right (and i know that i DID NOT) then i would drop a 3.1k resistor in series with two 1k tempcos to get 3500ppm?

lost as lost could be i'm afraid

steven

fonik · Posted: Mon Mar 05, 2007 10:34 am Post subject:

para · Joined: Oct 16, 2006 Posts: 276

seems like you did, your english is great, but i messed up assuming that the 50ppm was not a PTC but just a standard resistor. that part makes more sense now. so then this doesn't work right to get an accurate response out of using two series 1k PTC's because adding the third resistor/PTC will make the total resistance itself way off.

that said the math is beyond me. i've been out of school for too long.

zipzap · Posted: Mon Mar 05, 2007 12:49 pm Post subject:

they also have some intersting light dependant resistors.
i´ll mail you if i want to order anything. Good idea anyhow!

fonik · Posted: Mon Mar 05, 2007 12:50 pm Post subject:

amos_joseph · Joined: May 09, 2005 Posts: 50 Location: Lincoln, NE

This is great! I've been looking for a tempco source other than Ray Wilson. Put me down for 20.

ickystay · Joined: Nov 15, 2006 Posts: 143 Location: Oregon

I would like 20, please.

When I plug CA3080E into the search, I get a page that makes me wonder if they still carry them. Where other items would say "In Stock", this page says, "No Longer Manufactured". Pity.

bugbrand · Posted: Tue Mar 06, 2007 2:47 am Post subject:

Ok!

We're up to nearly 200 already - close to the 250 price break!
Great.

CA3080E - well, I'll see if they can supply any when ordering.. fingers crossed - it'd be good to get a batch at the same time though they're generally available from EBay regularly.

Steven Para -- ayeaye surething I can get all those bits (CA3080 maybe not but we'll see) - postage, obviously a bit more..!..

****

One note on all that maths -- are you remembering that these are 3000ppm rather than 3500ppm?

I'm not sure the formula works for 3000ppm resistors -- does this mean we've got a problem or is it insignificant? So, we're trying for 3300ppm?

TCR = (R1 x TC1 + R2 x TC2) / (R1 + R2)

3300 = (1000 x 3000 + R2 x 50) / (3000 + R2)

3300000 + 3300 R2 = 3000000 + 50R2

3250 R2 = -300000

R2 = approx -92R

....hohum....
(one presumption is that TC2 is 50 - but it'd work out negative anyways)

Thoughts on this?

****

One last thing - Paypal fees - I hope everyone is ok to cover the small paypal fees on transfers, otherwise I'll end up out of pocket. I'll do the order, get everything sorted for posting and then request pays from everyone - so no need to pay up front or anything.

Hopefully that way will be nice & easy!

fonik · Posted: Tue Mar 06, 2007 3:13 am Post subject:

para · Joined: Oct 16, 2006 Posts: 276

para is not my last name but i'm pretty sure already know that Smile

its just short for a bunch of titles i use. parade, parallel, parable, etc… oh and it means “for” in other languages which is nice.

-

so yeah, all the payment stuff is cool with me just let me know when. i can prepay if you need me too.

as for the tempco's conversion, all i care about is how to get these specific PTC's to act as 2k 3500ppm which seems to be the standard i see around. and that these PTC’s will give us the tuning that we after in the VCO’s i have now and will make in the future

thermal dynamics and algebra where we only know one value is not my thing. that 50 you are getting Bugs is another tempco that we will not have, so that is an open variable leaving us kicking our feet but going nowhere.

oh and the fact that i'm stupid doesn't help at all.

steven r.

fonik · Posted: Tue Mar 06, 2007 2:58 pm Post subject:

i don't want to discourage you but i have to go down to
20pcs
now, please. but that's now definately the count.
there's a groupbuy on the german forum i want to participate too.

bugbrand · Posted: Wed Mar 07, 2007 3:12 am Post subject:

bugbrand · Posted: Thu Mar 08, 2007 4:19 pm Post subject:

Ok, getting towards the final call..

I don't think we're quite at the 250 price break for the PTCs yet, so if anyone is....

There's people for both types of NSL vactrols so we're at least at the 1st price breaks for both of these. CA3080s, well, I'll try - hopefully a bunch.

Any final shouts, please let me know - I'll be ordering early tomorrow afternoon (UK time) for delivery hopefully next Monday (..so should ship out from here to you on Monday/Tuesday)
Cheers & Best

bugbrand · Posted: Mon Mar 12, 2007 6:13 am Post subject:

The order has arrived!

I will now PM everyone who expressed interest and should be sending everything out by tomorrow morning...

Edit -- PS - zero availability on the CA3080 and CA3046 unfortunately....

para · Joined: Oct 16, 2006 Posts: 276

Fernando · Posted: Tue Mar 13, 2007 12:00 pm Post subject:

sorry, I missed this thread, can I get 10 tempcos?

toppobrillo · Posted: Tue Mar 13, 2007 12:17 pm Post subject:

also, i just checked mouser, and according to them the lm13700 is now 'obsolete' as well. what do they have against OTAs? Crying or Very sad