John S <sophi.2@invalid.org> wrote:> Errr... The Wizard only tests ESR, yes? I don't think a comparison is > possible under the circumstances.<G> Yes, the comparison is a bit unfair, especially when the Wizard costs more depending on where you buy it.> If the TH2821A performs to the specs, then the money is minor and the > Wizard looses miserably.The TH2821A is an incredible value for the price. Apparently it is no longer being produced by Tonghui, and the TH2822 is much more expensive. So perhaps they are dropping the price to clear out the remaining inventory. According to an email I just received on the top853 USB universal programmer, apparently they ship via USPS to the States. So you might get yours a lot sooner, maybe 2 weeks instead of a month.> John SMike
Tonghui TH2821A LCR Meter
Started by ●October 31, 2011
Reply by ●November 9, 20112011-11-09
Reply by ●November 9, 20112011-11-09
On Wed, 09 Nov 2011 16:42:52 GMT, Mike <spam@me.not> wrote:>"krw@att.bizzzzzzzzzzzz" <krw@att.bizzzzzzzzzzzz> wrote: > >> On Tue, 08 Nov 2011 22:29:40 GMT, Mike <spam@me.not> wrote: >> >>> >>>John S <sophi.2@invalid.org> wrote: >>> >>>> Hey, Mike - >>>> >>>> How long did it take to get your meter? >>> >>>> John S >>> >>>I ordered it on Thu, 8 Sep 2011, it was shipped within a day or so, >>>and it arrived on Mon, 3 Oct 2011. >>> >>>That is about normal for shipments from China to Ontario, Canada. You >>>will probably see faster delivery in the US. I forget which delivery >>>service they used. Maybe it was DHL. >> >> Slow boat. ;-) I had a laptop (Lenovo) shipped from China on a >> Monday (China time) and it was delivered on that Wednesday, noonish, >> to my home in Alabama. It came UPS. > >I am in Canada, the land of polar bears and dog sleds. It snows here.It snows here, too. Twice last year, in fact. Scares the crap outta the natives. ;-)>I just ordered the top853 USB universal programmer mentioned by Nico >Coesel, http://www.ebay.com/itm/160378432470Neat.>I just received the following email from them: > > We shipped YOUR item from our office today. > > 1)If you are in United States, we ship your order via USPS First > Class mail Internationl. The estimated the delivery time is about > 7~10 days.It is amazing. DealXtreme ships to the US via airmail for a couple of dollars. It doesn't take anywhere near a week.> 2)If you are outside of United States, we ship your order via > standard air mail. > > The delivery shipping time is about 20~35 days according to your > countries. > >I lived in the States for 30 years before returning to Canada. I sure >miss the fast postal service you have down there. A letter across town >usually went overnight. Here, it takes 5 business days. That means you >have to add two more days for the weekend:)Next day within the state. If they had anyone who knew how to run a business maybe they wouldn't be going under.
Reply by ●November 11, 20112011-11-11
On 11/8/2011 4:29 PM, Mike wrote:> John S<sophi.2@invalid.org> wrote: > >> Hey, Mike - >> >> How long did it take to get your meter? > >> John S > > I ordered it on Thu, 8 Sep 2011, it was shipped within a day or so, and it > arrived on Mon, 3 Oct 2011. > > That is about normal for shipments from China to Ontario, Canada. You will > probably see faster delivery in the US. I forget which delivery service > they used. Maybe it was DHL. > > I really like the dissipation factor on electrolytics. You don't have to > measure the ESR, then go to a lookup table to figure out if that is the > proper value for the capacitance.I was not aware that there was a lookup table for this. Even if I don't need it, I'd like to see it. Where can I find it?> I just look at the dissipation factor, and if it's greater than about 0.2 > for an older cap, toss it. This is a big time saver. > > MikeHow did you determine a D of 0.2 is the limit? Tell me more about D and ESR, please. John S
Reply by ●November 11, 20112011-11-11
On 11/9/2011 10:42 AM, Mike wrote:> "krw@att.bizzzzzzzzzzzz"<krw@att.bizzzzzzzzzzzz> wrote: > >> On Tue, 08 Nov 2011 22:29:40 GMT, Mike<spam@me.not> wrote: >> >>> >>> John S<sophi.2@invalid.org> wrote: >>> >>>> Hey, Mike - >>>> >>>> How long did it take to get your meter? >>> >>>> John S >>> >>> I ordered it on Thu, 8 Sep 2011, it was shipped within a day or so, >>> and it arrived on Mon, 3 Oct 2011. >>> >>> That is about normal for shipments from China to Ontario, Canada. You >>> will probably see faster delivery in the US. I forget which delivery >>> service they used. Maybe it was DHL. >> >> Slow boat. ;-) I had a laptop (Lenovo) shipped from China on a >> Monday (China time) and it was delivered on that Wednesday, noonish, >> to my home in Alabama. It came UPS. > > I am in Canada, the land of polar bears and dog sleds. It snows here.You have my sympathies (unless you like that climate). I live near Dallas, Texas where the weather can go from 110F in the summer to (rarely) 10F in the winter. We are having a historical drought right now. At the moment it is 68F and sunny. I've entertained the idea of moving to Belize.> I lived in the States for 30 years before returning to Canada. I sure > miss the fast postal service you have down there. A letter across town > usually went overnight. Here, it takes 5 business days. That means you > have to add two more days for the weekend:) > > MikeThat is the major reason I have rejected the idea of moving to Belize. I am in the habit of getting the things I want from Mouser or Digikey or whatever in a couple of days. That wouldn't happen down there. John S
Reply by ●November 11, 20112011-11-11
John S <sophi.2@invalid.org> wrote: > I was not aware that there was a lookup table for this. Even if I > don't need it, I'd like to see it. Where can I find it? >> I just look at the dissipation factor, and if it's greater than >> about 0.2 for an older cap, toss it. This is a big time saver. >> Mike > How did you determine a D of 0.2 is the limit? Tell me more about > D and ESR, please. > John S Hi John, most of the ESR meters print a table on the front panel that shows the expected ESR for different values of caps. There are some examples on this page: http://members.ozemail.com.au/~bobpar/esrmeter.htm The Capacitor Wizard doesn't have a table. Instead, it has some vague instructions by Doug Jones, the designer of the Capacitor Wizard. Here is a section from one of the pdf files: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Well, finding those open caps and good caps was easy. Now lets look at other bad caps that require a little more experience with the Capacitor Wizard and some knowledge about capacitor TYPES and USES. You probably found caps from 1 to 30 ohms ESR in your bad box. How do you tell the good caps from the bad?? Whether the ESR of a particular capacitor is correct or too high can always be determined by comparing the suspicious capacitor to a known good one of the same value, voltage rating, and type. Unfortunately one doesn't always have another capacitor to compare against. Experience is the best teacher here, however there are some general guidelines: The higher the rated working voltage, the higher the normal ESR. Capacitors used in Power Switching applications need to have really LOW ESR - less than 1/2 ohm Nonpolar Caps are normally less than 1/2 ohm The next logical question about ESR is "How HIGH is TOO HIGH"? Thats a judgement call that can only be based on experience or comparison to a known good cap (or access to the engineering data from the capacitor or equipment manufacturer - ha ha!). Over 10 ohms is certainly too high for most applications. Over 3 ohms is too high for Horiz/Vert switching applications. Over 1/2 ohm is too high for power switching applications. By comparison you will gain experience and know when to be suspicious. These are my opinions. Here are some actual repair situations: Example: 47uf @50vdc measures 25 ohms ESR in circuit - BAD CAP The suspect capacitor is a 47uf @50vdc in a switching power supply for a VCR. The Capacitor Wizard has measured 25 ohms ESR in circuit. That is higher than 15 ohms and much to high for any quality cap. A new capacitor measured 5 ohms ESR. The new capacitor fixed the VCR. In my opinion the new capacitor was not of the highest quality (5 ohms is too high) however it did fix the VCR. The use of these low quality inexpensive import capacitors is probably the reason we see so much capacitor failure in con- sumer electronic equipment! A higher quality cap with a lower ESR of the same kind costs more money but will measure less than 1 ohm and be more reliable. Conclusion: This is a higher voltage capacitor and can be expected to normally measure higher than 1/2 ohm. In my judgment any "switch mode" capacitor that measures more than 3 ohms ESR is suspect no matter what the voltage rating. However you may obviously get by with the 5 ohms ESR in that particular circuit. For comparison, the bad part was checked "out of circuit" on a well known competitors $2000 Cap analyzer and it determined that the cap was GOOD - even though the ESR measured 25 ohms! That manufacturer made a huge mistake by trying to calculate good and bad ESR from entered and measured data. It can't be done reliably. That is why we don't simply have a good/bad indication on our meter scale. Any cap over 3 ohms is suspect. This is my Experience. Example: 1000uf @6vdc measures 1.5 ohms in circuit - BAD CAP This is a little brown 1000uf 6vdc cap used in lots of VCR switching power supplies. The Capacitor Wizard measured 1.5 ohms in circuit. Because the capacitors operating voltage is so low (6vdc) and its used in a switching power supply, I would expect a normal ESR reading of less than 1/2 ohm. Comparison to a known good cap confirmed it should measure less than 1/2 ohm. Replacing this cap cured the trouble. This particular cap goes bad often as I have many in my box of bad caps gathered from local repair compa- nies. If you work on VCRs, I bet you have some too. Summery: (mrm: sp) Measuring ESR is a very good indicator of capacitor failure. For switch mode circuits it is the ONLY reliable capacitor test, IN or OUT of circuit!. Open caps and caps with really high ESR (over 10 ohms) are easy to find in circuit and need to be replaced. Marginal caps that measure between 1 and 10 ohms ESR require some experience with the Capacitor Wizard and/or comparison to a known good cap of the same voltage, value, and type. Caps above an operating voltage of 35vdc have a normally higher ESR (around 1 to 3 ohms) than caps of a lower voltage (less than 1/2 ohm ESR). I know of no perfect formula or rule that can always tell normal ESR from marginal ESR other than comparison to a known good part. The obvious solution is to obtain the capacitor manufacturers data manuals on the EXACT capacitor measured but that is not normally practical. As a technician myself I always follow this rule: "If in doubt, replace". You will eliminate a lot of recalls and cure many weird and undefinable intermittent problems if you follow this rule. Doug Jones, Designer of the Capacitor Wizard http://midwestdevices.com/_pdfs/FirstTime.pdf ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ To find a typical dissipation factor for the Tonghui, I went through several boxes of old electrolytic caps. Regardless of the capacitor value, there seemed to be a clear dividing line between good and bad caps. I settled on D = 0.2 as it seemed to be a reasonable number for most applications, such a bypass and coupling caps. However, if the application was critical, such as a capacitance multiplier for low level dc supply, I'd look for capacitors with the lowest D value I could find, and put some in parallel. The interesting thing, and this has me a bit confused, is the dissipation factor does not seem to be affected much by the test frequency. I would expect the ESR to remain fairly constant with frequency, but the capacitive reactance of course will change. So the impedance of the capacitor will change with frequency, and I would expect the dissipation factor to change also. I haven't had time to sort this out yet, and I need to get some more experience with this instrument and find out how it is making the measurement. For example, take a known good capacitor and add some series resistance and see what happens to the readings. But here are some wikipedia references to start with: Equivalent series resistance http://en.wikipedia.org/wiki/Equivalent_series_resistance Dissipation factor http://en.wikipedia.org/wiki/Dissipation_factor Mike
Reply by ●November 11, 20112011-11-11
John S <sophi.2@invalid.org> wrote:> On 11/9/2011 10:42 AM, Mike wrote:>> I am in Canada, the land of polar bears and dog sleds. It snows here.> You have my sympathies (unless you like that climate). I live near > Dallas, Texas where the weather can go from 110F in the summer to > (rarely) 10F in the winter. We are having a historical drought right > now. At the moment it is 68F and sunny. I've entertained the idea of > moving to Belize.Winter is not so bad. You get used to digging your car out of snowbanks and scraping ice from the windshield. There were two things I didn't like much about the states. One was the smog in most cities. That started to make me sick. Now I can't even go near Toronto when it is bad. The other was teenagers with 9 mm and .45 firing them in alleways at night. I got a scanner and started listening to the police trying to catch them. I guess they had scanners also, since I never heard of anyone getting caught. The nights are very quiet here in Midland, Ontario. The police transmissions are encrypted, so it's a waste of time trying to listen. I used to be able to tell the difference between a 9 mm and a .45, but I haven't heard one for such a long time that I probably forgot what they sound like.>> I lived in the States for 30 years before returning to Canada. I sure >> miss the fast postal service you have down there. A letter across town >> usually went overnight. Here, it takes 5 business days. That means you >> have to add two more days for the weekend:) >> >> Mike > > That is the major reason I have rejected the idea of moving to Belize. > I am in the habit of getting the things I want from Mouser or Digikey > or whatever in a couple of days. That wouldn't happen down there. > > John SI'd move to Bangkok in an instant. Except right now they are having problems with flooding. But you can get just about any electronic component in minutes, at very cheap prices. And the girls are soooo nice:) Mike
Reply by ●November 11, 20112011-11-11
On 11/11/2011 4:05 PM, Mike wrote:> John S<sophi.2@invalid.org> wrote: > > Winter is not so bad. You get used to digging your car out of snowbanks > and scraping ice from the windshield. There were two things I didn't like > much about the states. One was the smog in most cities. That started to > make me sick. Now I can't even go near Toronto when it is bad.Yeah. I'm on the north side of Dallas and I can smell the fumes when I go outside.> The other was teenagers with 9 mm and .45 firing them in alleways at > night. I got a scanner and started listening to the police trying to > catch them. I guess they had scanners also, since I never heard of anyone > getting caught.Don't have that around here yet, thankfully.> The nights are very quiet here in Midland, Ontario.Usually quiet here, too, except for the annoying loud bass thumping from cars driving by.>> That is the major reason I have rejected the idea of moving to Belize. >> I am in the habit of getting the things I want from Mouser or Digikey >> or whatever in a couple of days. That wouldn't happen down there. >> >> John S > > I'd move to Bangkok in an instant. Except right now they are having > problems with flooding. But you can get just about any electronic > component in minutes, at very cheap prices. And the girls are soooo > nice:) > > MikeI have friends who are pushing me to retire to the Philippines. They say I can have one or more live-in maids, a beachfront house, etc for less than my monthly costs now. It is persuasive.
Reply by ●November 11, 20112011-11-11
On Fri, 11 Nov 2011 16:43:08 -0600, the renowned John S <sophi.2@invalid.org> wrote:> >I have friends who are pushing me to retire to the Philippines. They say >I can have one or more live-in maids, a beachfront house, etc for less >than my monthly costs now. It is persuasive.Foreigners are not allowed to own land in the Philippines, let alone beachfront property, which is probably just as well. Long term leases (eg. 50 years) are possible. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Reply by ●November 11, 20112011-11-11
On 11/11/2011 4:53 PM, Spehro Pefhany wrote:> On Fri, 11 Nov 2011 16:43:08 -0600, the renowned John S > <sophi.2@invalid.org> wrote: > >> >> I have friends who are pushing me to retire to the Philippines. They say >> I can have one or more live-in maids, a beachfront house, etc for less >> than my monthly costs now. It is persuasive. > > Foreigners are not allowed to own land in the Philippines, let alone > beachfront property, which is probably just as well. Long term leases > (eg. 50 years) are possible. > > > Best regards, > Spehro PefhanyI'm 70. I don't need to own anything anywhere. I'm renting life (and beer) as it is.
Reply by ●November 19, 20112011-11-19
On 10/31/2011 9:58 PM, Mike wrote:> Here's something that may interest some folks here. I just got my new > Tonghui TH2821A LCR Meter, and I'm starting to become quite impressed.Hey, Mike - Mine came in yesterday. Since the wall wart is 220V, it is useless to me so I cut the chord and used a lab power supply to charge it. This got interesting. With the meter off, the current was only about 5mA. I turned the meter on and the current went to about 140mA. After a period of time which I did not measure, the current dropped back to about 50mA and the battery symbol indicated full charge. This makes me wonder if fast charge takes place only when the meter is on and it just trickle charges with the meter off. Have you noticed a long charging time with the meter off? Cheers, John S
