Low Cost PCB's Low Cost Components

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Beginners / Budget soldering iron
« Last post by Gmm213 on Today at 07:16:53 PM »
First off let me say take pity on me lol. Im sure you guys hear this question all the time. I searched and found some ideas for irons but mostly cam across rework stations. Let me preface by saying that I am not a beginner when it comes to electronics or electrical. I did it daily in the Navy.

I was hoping for some help settling on one specific iron. This will get used a handful of times a year for random projects I come across. I was hoping to stick to a budget of $50. So far I have found:

1) Weller WLC100
2) X-Tronic 3xxx
3) Aoyue 469
4) unbranded 862D+ SMD rework
5) Any other recommendations?

I like the idea of the Weller for the name brand but Im worried the 40w will limit me. I dont need an entire rework station but if I had it Id use it. The iron itself is much more important. As for stretching to the always recommended Hakko FX880 I figure if I use one of these enough to justify it to myself Ill probably go with something nicer than that down the line.
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General Chat / Re: Next iteration of NBN madness Fibre to the Curb
« Last post by Rerouter on Today at 07:15:24 PM »
Well even pre NBN, the ISP's already had baked in to just about every modem i have ever owned an ISP side way to pull the full SNR and attenuation per channel info from the modems, It really would have only taken an intern a week to start pulling that data, correlate it to when it rains and flag cable pits that are likely not sealed well. Same for houses that drop massively when it rains, or houses in general that are well below the norm,

But this was in the days of "Up to" speeds, where as long as you could connect more than half the days in the month they stopped caring (you ask for a refund on the non serviced days and they send out a tech pretty fast)

To clarify, they already have the info gathering sources in place to flag the worst cases,
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Good feedback GigaJoe. Maybe I should sell it with removable cells like Eneloops and just count on the user to replace them periodically?
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Beginners / Re: Speed control for disk sander using variac
« Last post by Benta on Today at 07:10:24 PM »
Mains-supplied hand tools and smaller table-top machines usually have a universal motor. This can speed controlled with a simple Triac-type dimmer.
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In my Siglent SPD3303D power supply there is the same problem for an otherwise good device: no velocity for the knob ...

to be honest: i really hate devices with velocity in the knobs.  :-[ It happens so often that i want to increase some value by a small amount - and when turning just a little bit too much it makes huge steps into an area of damage.

So the rigol-solution (they are using the same principle i.e. in their DG1000Z function generators line) where you can preselect the decimal place where you do your changes is not really a bad one. Sometimes it is annoying too - but you always have full control.

In my opinion the DL3021 is not a really bad device and it is much better in many points than i.e. maynuo, BK or itech devices. But it has some design flaws that may be a showstopper for some people (for me it was the 3,5 MHz oscillation observed... some data that were completely out of spec ... and the huge size of the device compared to its load capabilities).
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Depends what you mean by cost effective.
If you also want it quickly it's going to be expensive. For small batches it's dominated by setup costs, and also the fact that most subcontractors can only use large stencils, and haven't discovered Far-East stencil suppliers.
 So you're typically looking at £160-200 per side for stencils and £100-300 setup/programming before you get the first board out.
Per-placement cost ranges between 3-10p
I currently use two UK places :
PSL  http://www.printsys.co.uk/ They have lots of capacity and a dedicated line for fast turnrounds, and can do up to 1.6m long boards

http://www.fringeelectronics.co.uk/  Smaller outfit, usually a bit cheaper than PSL but not so quick and timescales can be somewhat variable.  They also charge stupid money to do sourcing and their usual PCB supplier tends to be expensive so I usually supply all parts and PCBs.

There's also  http://www.hcduk.com/ who can specialise in small jobs and can turn stuff round very quickly and do a good job but very expensive IME (>10p per placement + £200/side stencils)

I've heard good reports for Quick Teck http://www.quick-teck.co.uk , who are a UK office dealing with Far-East manufacturer(s) with online quoting for small jobs. I compared their costs to a few recent jobs from PSL and costs were similar.

PLEASE let me know if you come across anywhere interesting.
 
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Here is the List of CPU thermal designed power from https://en.wikipedia.org/wiki/List_of_CPU_power_dissipation_figures

If the cooler was designed for it, would it be safe to assume those figures relatively speaking?
These are the ghetto pentium 4 CPUs for poor people. Pentium 4 went up to some 130W, and they were easily dissipating above their TDP limit.
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Beginners / Re: Why oscilloscopes dont have AC coupling for 50 ohm input
« Last post by Benta on Today at 07:07:28 PM »
If the inputs are AC coupled, you can't measure DC signals, which would be a major drawback. Neither 50 ohm nor 1 Mohm inputs are AC coupled on the 'scopes I know. AC coupling is done in the probe.
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Test Equipment / Re: Why CAT ratings are so important AND safe practises
« Last post by Z80 on Today at 07:06:38 PM »
Some good points raised and it all applies to pros as much as hobbyists, but I exclude pros because they should already be aware of the hazards and don't need me or anyone else to teach them to suck eggs.  I totally agree that CAT ratings are just a certificate of compliance to a standard and not an indication of suitability for any particular scenario, that is an important distinction.  Taking the title of this thread, I would reverse the order and say that 'Why safe practices are so important and cat ratings', that's the message I'm trying to convey.  For example there is often mention of the 'annoying' insulation socks going down to the probe tip, well I unfortunately have had first hand experience of a colleague who had a bad habit of resting his fingers on the probes when measuring.  Not a problem 99% of the time but the occasion he went to measure a live transformer primary was a different story and I had to kill the power before it killed him.  He was 'live working' certified, but that training didn't mention not touching the probes, maybe it was too obvious.  There are many other examples like this I can quote.  There is unfortunately a lot of snobbery and almost evangelistic rantings here sometimes when it comes to test gear and particularly dmms.  This forum has a lot of respect associated with it so it would be easy for the uninitiated to believe it literally.  I have a lot of respect for mains electricity and everyone else should have to, but there is a gaping chasm between what you get in your home and what you get in a factory and the two should not be confused.
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It is not a bug..

How do you provide current? You use constant current source or maybe voltage source with resistor in series?

Watch the video, constant current source Keithley unit.

Oh really, so I should just be OK with not being able to measure part of the range? How would you like an instrument that advertises 0.001V-300V range, except 2-5V doesn't work.
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