Are these LM35DZ parts bad?

JohnInTX

Joined Jun 26, 2012
4,787
Excellent work @Lestraveled ! I was done at 'bought them on eBay' but you are the man!
So what you are saying is that you can't always depend on a 99.x% rating from eBay?? Crushed, I am.
Just. Crushed.

And yet, here I found the exact part from aliexpress.con



Love your amber LeCroy and have the same HeathKit curve tracer although I haven't used it in years.. It has the older brown wrapper, like me.
 

Thread Starter

Roderick Young

Joined Feb 22, 2015
408
So what you are saying is that you can't always depend on a 99.x% rating from eBay?? Crushed, I am.
Just. Crushed.

And yet, here I found the exact part from aliexpress.con
Apparently, as soon as a company refunds your money in full, it's as if the transaction never happened, and you are unable to leave feedback of any kind.

If find it interesting that the LM35 parts in the picture are datecode 36RA. What a f#@ing coincidence that they are exactly the same datecode as my bad parts. When I got good parts from another source (possibly also originally from China, who knows), they were a different datecode.
 

JohnInTX

Joined Jun 26, 2012
4,787
Apparently, as soon as a company refunds your money in full, it's as if the transaction never happened, and you are unable to leave feedback of any kind.
I find it interesting that the LM35 parts in the picture are datecode 36RA. What a f#@ing coincidence that they are exactly the same datecode as my bad parts. When I got good parts from another source (possibly also originally from China, who knows), they were a different datecode.
Yeah, I googled LM35 and it just popped up in 'Images'.
What a scam. Your refund is essentially held hostage to not posting a bad review. I've seen some shady stuff over the years from brokers and grey market vendors but this is overt fraud. Presumably the model works because lots of buyers wouldn't bother with going after a small refund and the sellers win.
Glad you at least got your money back and kudos to the others that tracked down the truth about the parts. If nothing else, this thread serves as a cautionary tale for those that think that these guys have some magical way of providing parts at super low prices.
 

dl324

Joined Mar 30, 2015
17,142
Hopefully the Chinese Government will come to understand that not cracking down on counterfeiting will continue to have a negative impact on their economy and the perceived quality of their manufactured goods.

There's a $500 CNC Mill being discussed in another thread. The price looks good for an entry level machine, but the fact that it's made in China is now clouding my decision. That and the fact that the quality of legitimate products usually decreases over time because factories make cost saving changes that go unnoticed for awhile by the buyers...
 

JohnInTX

Joined Jun 26, 2012
4,787
Hopefully the Chinese Government will come to understand that not cracking down on counterfeiting will continue to have a negative impact on their economy and the perceived quality of their manufactured goods.
Don't count on it. The level of corruption throughout the whole country is breathtaking. There have been quite a few high profile arrests and even executions but it goes on. The government is trying to hunt down (literally in some cases) various ministers who have set up havens outside of China but its a drop in the bucket. Returning from a China trip last year, the big headline was the arrest of the minister for coal fired power plants - he had $32million in cash in his house. This year, smog in Beijing is still a big story... One problem is that their government realizes that it can't maintain the kind of %GDP growth that they have had if they require pollution controls, crack down on corruption etc. Its a mentality that pervades the whole outfit.

As far as a $500 CNC mill - there ain't no such thing.
[/rant]
 
The LM35 series are precision integrated-circuit temperature sensors, with an output voltage linearly proportional to the Centigrade temperature. Thus the LM35D has an advantage over linear temperature sensors calibrated in ° Kelvin, as the user is not required to subtract a large constant voltage.
 

dl324

Joined Mar 30, 2015
17,142
Welcome to AAC!
I have the same problem. Bought some eBay junk LM35's apparently. Marked to look like National parts, but absolutely no output.
Does the surface seem to have been blacktopped or the leads pitted like they've been sandblasted (or re-tinned to make them shiny)?

Do a diode check between the pins to see if they might be transistors.

eBay and Ali Express are risky places to buy components these days. Amazon could have people selling counterfeit components. Don't be fooled by some thinking low prices means counterfeiting isn't likely. The cost of living in most of China is low and a few dollars a day is sufficient incentive to strip parts from discarded electronics.
 

jursoleo

Joined Oct 25, 2021
1
Welcome to AAC!
Does the surface seem to have been blacktopped or the leads pitted like they've been sandblasted (or re-tinned to make them shiny)?

Do a diode check between the pins to see if they might be transistors.

eBay and Ali Express are risky places to buy components these days. Amazon could have people selling counterfeit components. Don't be fooled by some thinking low prices means counterfeiting isn't likely. The cost of living in most of China is low and a few dollars a day is sufficient incentive to strip parts from discarded electronics.
They are in the trash can where they will stay. :)
 
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