Out of curiosity, I made an informal test on a random selection of capacitors of various epochs and origins, and to my surprise, I found a relatively large number of mismarked caps.
I only tested the ones that were marked unambiguously, and I used a deterministic method.
Of those tested (several dozen), the majority was OK, but more than 10% were mismarked:
Not something I expected, especially from well-known and reputable manufacturers.
Morality: take nothing for granted.
Designing a really effective, reliable and easy tester is probably worth the trouble for people requiring such a certitude about polarity (the existing testers displayed are a bit too flaky and haphazard).
I only tested the ones that were marked unambiguously, and I used a deterministic method.
Of those tested (several dozen), the majority was OK, but more than 10% were mismarked:
Not something I expected, especially from well-known and reputable manufacturers.
Morality: take nothing for granted.
Designing a really effective, reliable and easy tester is probably worth the trouble for people requiring such a certitude about polarity (the existing testers displayed are a bit too flaky and haphazard).
Attachments
Mr. Carlson’s Lab SIFT DEVICE
I restore vintage audio amplifiers and guitar amps. Paying $2.00 a month for Carlson’s Patreon account is super inexpensive education and access to his inventions. I have built several of his inventions. The SIFT DEVICE is awesome. It works fantastically! It takes some practice creating the PCB board and working with such tiny surface mount components but well worth the effort. THE MORE YOU DO THE EASIER IT GETS!
It’s fun too!
I restore vintage audio amplifiers and guitar amps. Paying $2.00 a month for Carlson’s Patreon account is super inexpensive education and access to his inventions. I have built several of his inventions. The SIFT DEVICE is awesome. It works fantastically! It takes some practice creating the PCB board and working with such tiny surface mount components but well worth the effort. THE MORE YOU DO THE EASIER IT GETS!
It’s fun too!
This tester is completely automatic, deterministic, and does not rely on stray fields to operate:
ƑƠɭįƠ is a simplistic, yet automatic outer foil tester for capacitors
It is also inexpensive and requires only a single battery.
ƑƠɭįƠ is a simplistic, yet automatic outer foil tester for capacitors
It is also inexpensive and requires only a single battery.
Elvee,
Your circuit is simple and elegant. It is well thought and engineered just like the rest of the designs you’ve freely shared. Kudos!
On the other hand, I’m guessing Paul’s SIFT will use an opamp, mostly SMD parts just because, tantalums and his favorite LM3914 for the display. This is his MO for at least 10 years now. I personally know Paul and his “inventions” are not well designed, they are quite predictable. I didn’t use the word engineered since he is not an engineer. Sorry to his fans out there but that is the reality. His PCB layout style is a hint of his actual capacity.
Between the two designs, I would pick Elvee’s outer foil tester.
Thanks, I always try to offer real DIY alternatives whenever possible: for some people, the comfort of an (almost) ready-made instrument is preferable, but others find it interesting to get more involved, have a bit of sweat, overcome the difficulties and end up with something more personal and superior compared to easier solutions.
And in the process, they will have sharpened their skills and become better at their hobby (or even their work, who knows).
For that reason, I strongly encourage mods, tweaking and discussion: it is an excellent way of learning, and not only for the users of the project: the designer can also gain a thing or two in the process
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.