Atlas dca model:DCA55 any good?

[carbon dude oxide]

Hello, where i work we sell an atlas DCA55 (semiconductor componant tester) and i would like to know if its any good. I have tried it a few times at debuging a couple of customers products, such as some broken triacs but is it work getting one?

[alank2]

I've had one for a couple of years and I find it handy to use from time to time.  No problems with it.

[lemon]

Very usefull tester.
Look and DCA Pro, too! The curve tracer function is very good.

[carbon dude oxide]

Ok thanks

[carbon dude oxide]

I can get the pro for £87 where i work ^.^ is that a good price?

[lemon]

Yes, it has £115.95 inc VAT
http://www.peakelec.co.uk/acatalog/dca75-dca-pro.html

[Tube_Dude]

I have one DCA55 and love it. No more need for checking in the data sheet the pinout of any transístor... 

[FlyNN]

I've had one for a few months and am pleased with its operation. A good piece of test equipment to have on the bench.

[PA4TIM]

I got one too.
Pro:
- Very handy to check pins from transistors.
- small
- works 99% of the time well

Downside:
- unusual 12V battery.
- hFE measurement is more an indication.
- Do not trust it blind. I have seen strange things and a friend too. Like a bad transistor he called a fet . Also two times a bad transistor that was stated good (i have a Tek 576 curvetracer,  a Tek R Transistor timing plugin and a bunch of transistor testers)
-very flimsy testleads and clips/
- small  (to much gear in my lab so I loose it)

[Psi]

I have one too and am very happy with it.

But yeah, look at the pro version, its got more features that maybe worth getting.

[PeakAtlas]

Dear All,

I've just joined, so apologies if I've missed stuff. please point me in the right direction if anyone thinks I should be aware of something!

Anyway, pleasure meeting you all on here and I hope I can make the odd useful contribution.

You probably already know that Peak Electronic Design Ltd is a fairly small company in  the UK, but that doesn't mean we don't try really hard to make things as good as possible 

Being little, we can be flexible and even make changes based on customer feedback fairly quickly, so if anyone has any suggestions, complaints (be gentle!) or anything else to say then I'd be delighted to hear.

On that subject, PA4TIM mentioned a few points that I may be able to help with. We changed the test leads and test clips about 3 years ago to a much sturdier set that is still universal enough for most parts but much stronger that the old type. Drop me a line if you think you've got the old type (new variety is picture attached). PA4TIM also mentioned the odd battery type. Yes, I agree, the 12V battery is fairly unusual (compared to AA and AAA for example), but are still fairly easy to get hold of from auto shops or electronics shops. The duracell equivalent is MN21. They're available from us directly too if you're stuck.

Anyway, enough waffle for my first post. Don't hesitate to prod me if there is anything I can help with.

All the best,
Jez Siddons

[ddavidebor]

12v battery is pre dc-dc converter stuff.

I suppose in a few year (alredy is difficult to find) it will be anywhere. No one shop will sell it.


First suggestion, redesign the power supply. With all the dcdc goodness from mobile phone tecnology, there is no reason to use an absolete battery.

It's design lazyness from my point of view.

[alank2]

Hi PeakAtlas,

I've got a couple of your products and they are quite handy.  I especially like the delay before scanning feature so you don't have to have a third hand on one of them.

Thanks,

Alan

[PeakAtlas]

Hi David, thank you for your comment.

The MN21 style battery does indeed have a long heritage and is still fairly popular in remote key-fobs, wireless doorbells, wireless alarm nodes, some photographic gadgets as well as some bits and bobs (such as some of our analysers). I agree entirely that it isn't the easiest battery to find, but there are many manufacturers out there that make it (see attached). I suspect that the big electronic distributors will supply them for many years to come. I've even seen them in my local stationers (WH Smith in the UK).

In terms of design choices, it is horses for courses really. It does have the very notable feature of being very small and much more cost effective than coin cells for the user. in terms of size, the 12v battery is 50% the volume of an AAA cell. Additionally, the current consumption of the DCA55 is below 5mA most of the time while switched on. Using a switching PSU design for a low current consumption application is surprisingly power inefficient. Most switching PSU designs run at good efficiencies for currents above several 10's of mA. Hence their use in mobile phone type applications as you point out.

Furthermore, for devices that are measuring fairly small parameters, switching power supplies can be pretty noisy and often have to be followed by a linear LDO to remove the noise completely (filtering is not always as effective as you need). Our Atlas SCR and Atlas DCA Pro products use a switchmode with a post-regulation of a linear LDO (they both use a single AAA cell). The consumption of both of those instruments however is much higher than 5mA and so the efficiency of the switchmode approach becomes sensible. Additionally, they are higher value products and can better stand the cost of the switchmode parts.

So for our products that do have a very low current consumption, we find the use of a linear LDO offers a good combination of clean supply and good battery life (battery can go from 12V to 7V and stilll be operational).

I can't pretend our designs are perfect, but I don't think we've been lazy in our design choices, more a case of applying the most appropriate parts for the application. We will always consider the availability of consumables in our design choices too.

Best regards,

Jez

[PeakAtlas]

Hi Alan,

Thanks for your message, much appreciated. Delighted that you like your instruments.

Cheers,

Jez

[jucole]

I bought a DCA55 recently and I'm pretty happy with it;  I also like the fact they are based not too far away - just in case I drop it into my coffee by accident ;-)

[PA4TIM]

Jez, mine is indeed older as 3 years. I noticed the later ESR 70 also had other leads. Idid not buy them but got them from a friend who had them surplus. So no clue about the age.

http://www.pa4tim.nl/?p=3319

I solved the leads problem like you see in the link above. They aways got lost in between tools and gear so I put them in a cabinet with mains supply.

I realy like the component tester and I use it often. However for serious testing while designing or repairing I most times a use a Tek 576 curvetracer.
I took a 3 pin din-socket and pins from an IC socket. I presolderd the pins, and the inside of the socket, heated the pins from the socket and pushed the IC pins in. This is much more easy for testing.
Besides that I have mounted 3 banana sockets and I can plug my own clips in there.

The ESR 60 is also good, I have done a lot of ESR measurements and this little thing is rather accurate and realy measures ESR instead of impedance. The C function of the 60 and 70 is not good when caps are bad, so just in the situation you need the ESR meter.

I have done a lot of tests on bad caps using everything from impedance and LCR bridges to network analysers. The problem with bad caps ( DC leakage, loss of capacitance and high ESR)  is that the C measurement using DC totaly goes wrong, the ESR and/or leakage is the cause of this.
In a new test a few weeks ago using the 60 and the 70 and some Multimeters, they all went wrong. You find that test on my site ( in english, measuring ESR on bad caps)

But sorry to say, in my opinion the LCR meter ( but I have an old version) is a disaster. For electrolityc caps it used DC again, under 10 pF ( or RF work conponents) it is not good either, but for allround LCR measure gismo to check if you got the good ceramic cap, or the value of a not RF coil, a resistor it is OK. The auto measurement is handy but not allways. Like this afternoon I was doing some tests on inductors and my IET DE-5000 thought I had a resistor (it was a GR 50-100 mH inductor) but in that case can switch off auto and choose a mode.

On all I do not like the auto power of. I understand it because the battery life. But it is not handy, picture a multimeter where you have to do this each measurement. It would drive me crazy.

Hope you see this as positive points, i do not mean to talk your stuff down. Just the opposite. I get many questions about sopes, multimeters, LCR and VNAs and several people bought the ESR meter after my advise.

[PeakAtlas]

Hi PA4TIM,

Many thanks for your comments, they are much appreciated and very useful to us. I will see what we can do to improve things in the areas you mention.

By the way, we have extended the on-time of our ESR60/70 in recent years as we have been able to implement improved power management software that has been possible with more recent micros.

I've seen your images,  I've never seen anyone do that before with multiple units, that is very interesting.

Kindest regards,
Jez

[Owen]

The ESR 60 is also good, I have done a lot of ESR measurements and this little thing is rather accurate and realy measures ESR instead of impedance. The C function of the 60 and 70 is not good when caps are bad, so just in the situation you need the ESR meter.

Great tests ! I like it. But which Peak ESR would you recommend? In practical: Is there any advantage over the 60 model? Would you recommend these or would recommend the a "real" LCR meter with ESR function?

[Salas]

Our Atlas SCR and Atlas DCA Pro products use a switchmode with a post-regulation of a linear LDO (they both use a single AAA cell). The consumption of both of those instruments however is much higher than 5mA and so the efficiency of the switchmode approach becomes sensible. Additionally, they are higher value products and can better stand the cost of the switchmode parts.

Hi

What is the consumption for DCA Pro? Does it absolutely stop drawing from battery when connected to PC?

[PeakAtlas]

Great tests ! I like it. But which Peak ESR would you recommend? In practical: Is there any advantage over the 60 model? Would you recommend these or would recommend the a "real" LCR meter with ESR function?

The *main* advantage of the ESR70 over the ESR60 is the audible feedback tones. The ESR70 generates little "bell-like" tones to indicate various thresholds of measured ESR. It also does a "beep-barp" when it detects a very high ESR. This allows you to bob along various capacitors in turn, listen for the tones and you know when you've got good, medium or bad ESR just from the nice tones.

The ESR70 does also have double the ESR measurement range (40 Ohms instead of 20 Ohms) although it is rare that you're interested in the actual value of ESR if it's above 20 Ohms anyway, it's a pretty poor capacitor that would have an ESR of 20+ ohms.

Both the ESR60 and ESR70 have an automatic controlled discharge function so are better protected against charged caps compared to some LCR/ESR meters out there. They don't just clamp the probes with a pair of diodes, they perform a highly controlled "constant power" discharge until the voltage is sufficiently low so that it can then proceed to do an ESR measurement.

Both the ESR60 and ESR70 have the same measurement resolution of 0.01 Ohms and this is measured at the "industry standard" of 100kHz that most capacitor manufacturers like to specify.

The capacitance measurement function is a secondary measurement for the ESR60 and ESR70. It's main task is to measure ESR (which it can do in-circuit in most cases). Capacitance is generally measured if the capacitor is out-of-circuit but can be handy as an additional confidence indicator of a capacitor's condition.

Cheers,

Jez

[PeakAtlas]

Hi
What is the consumption for DCA Pro? Does it absolutely stop drawing from battery when connected to PC?

The DCA Pro doesn't draw any current from it's AAA cell when it's connected to a powered-up PC. In fact, you don't need a battery in it at all when you're connected to the PC.

Cheers,
Jez

[Salas]

Why the DCA Pro changes VDS when testing various types JFETs IDSS? It would be nice if it could stay put so the readings can be comparable. Like 10V VDS for instance. Also what is the accuracy for HFE tests?

[PeakAtlas]

Why the DCA Pro changes VDS when testing various types JFETs IDSS? It would be nice if it could stay put so the readings can be comparable. Like 10V VDS for instance. Also what is the accuracy for HFE tests?

Hi,
I will investigate your question about the V_DS when testing JFETs. I do know that the DCA Pro (in stand alone mode) attempts to use a constant current of 5mA for the I_DS, although that can be lower if the JFET has a lower saturation current than that. Like I say, I'll investigate the V_DS question a little further and answer you properly.

In PC mode, you have much greater flexibility on the test conditions for measuring various parameters. The parameters are automatically populated when you first do a fresh component analysis but you can still choose your own. You can even export your data to Excel or Open Office if you want to calculate some further parameters (such slope resistances etc).

In answer to your H_FE accuracy question, the H_FE is measured to an accuracy of nominally ±3%.

I hope that helps,

Jez

[Salas]

Thanks for the accuracy spec. Whenever IDSS is >5mA it shortens VDS. I think that it would be useful to keep that parameter steady and independent.