TL072 fries easily?

deadsnake · February 27, 2006, 03:54:21 PM

Hi I would like no know If the IC TL072 would fry if I reversed the polority (used pin 8 as - and 4 as +).

The Tone God · February 27, 2006, 04:43:33 PM

There is a good chance.

Andrew

deadsnake · February 27, 2006, 04:53:32 PM

I did that you know. So I guess it´s fried. they are quite expensive for a IC they cost like 3 bucks

Lurco · February 27, 2006, 05:00:56 PM

where do you pay more than 20 cents for that?

deadsnake · February 27, 2006, 05:12:53 PM

dang........ here in brazil things are a quite expensive.........

I could have bought a bunch of them and test them until I got it right hhehehehe

Sir H C · February 27, 2006, 05:14:08 PM

Yes it will definitely fry. Sadly, this is because they want to make them safer for you to handle so there are a lot of protection diodes internally so when you reverse the supply, you have two diodes in series from rail-to-rail, poof!

deadsnake · February 27, 2006, 05:19:17 PM

Well you helped me a lot man. I just did that and I think this is why my project isn´t working. I´m going to reaplace it tommorow. it´s carnaval here in Brazil, nothing opened besides bars. ThanX

gtrmac · February 28, 2006, 03:25:32 AM

Just for your information:

I order parts from Mouser and have them shipped to Japan via US Postal Service Air Mail at a reasonable price. I only do this for certain parts that I can't easily find here in the local shops. I try to make the orders around $50~$100 and the shipping is usually about $15 so it works out OK. All you need is a credit card.

$3 for a TL072 is way too much, you could get a bunch of stuff from Mouser and the savings would pay for the shipping.

I hope this helps.

Paul Perry (Frostwave) · February 28, 2006, 08:51:01 AM

I have the idea that postage and customs in Brazil is more difficult than most places. Certainly, most of my Brazilian customers have waited until a friend could buy from me while visiting Australia.

StickMan · March 01, 2006, 12:38:27 AM

I can't believe that the customs in Brazil is going to be all that finicky about a $5.00 shipment. Order a dozen from mouser or SmallBear, it should still come under the $5.00 mark. Shipping will run another $5.00. That's still only $0.80 a piece.

When I get stuff shipped into Canada from the States, I try to keep the amount under $20 or $30. There's a secret magic number somewhere in there that triggers Customs and Revenue Canada to go to the trouble of assessing the value and collecting taxes. When they do that, they pretty much always add a $10-$20 handling fee on top of it. I bet most countries are a bit like that, and it's just a matter of knowing how the system works.

dave.

Xlrator · March 01, 2006, 03:45:20 AM

There's a carnival going on outside your house and you are building pedals! Kinda hard to put down?! Add another addict to the list!!

deadsnake · March 01, 2006, 10:55:05 AM

A friend of mine invited me to go to a club where carnaval bombing......... I choose to stay home......... I´m not really a party guy but I enjoy it when I´m drunk. So I was building my wah pedal ans stuff and I was cutting this screw that its tip was sticking out of a crucial part of the pedal, I was using a dremel with a improvised metal disk that I made using some junk shielding of a Nintendo System (I should have sold It to collectors and asked for a good price) so that dremel with that disk that acted as blade instead of a "scraping disk", was taking too long to cut the darn thing. I forced it to cut applying more muscle power to the piece, the dremel rolled( as it was a weel spining at 35,000 rpm) like a crazy dodge charger rt and went right on my right thumb. It did a quite deep cut and I got 3 stitches, I´m not going to play guitar for at least a week. I cannot hold a dremel anymore........ at least for a week.

well anyway here a pic of my thumb, if you are eating i´s not a good idea.
http://img206.imageshack.us/img206/1160/imag01239kz.jpg

theundeadelvis · March 01, 2006, 11:16:23 AM

I've had a couple of injuries similar to that one and it always seems that right before it happens I think to myself "hmm this is a bad idea, I am probably going to hurt myself" then BAM! a trip to the ER. Hope you heal up fast!

jmusser · March 01, 2006, 06:43:34 PM

In my experience, the TL0 chips are pretty tolerant to miswires. I have gotten disoriented on my pinouts, while going from the top of the perf to the bottom of the perf, and had them wired all sorts of ways. When I rewired them correctly, they have always worked. So, you could potentially just have a miswire still. I have also pulled a variety of op amps out of old crap boards that have been thrown around in boxes for Lord knows how long, and they most always work. Now, the 4049, 4046, and especially the 4070 XOR chip, seem to be pretty sensitive, and can't tolerate even much handling, let alone miswiring. That's just my 2 cents.

deadsnake · March 01, 2006, 07:23:05 PM

Thanks. I´ll not bother taking care of it anymore hahahah. I bought some TL082 which can substitute the TL072 which was supposed to be fried

Nasse · March 02, 2006, 02:04:56 AM

Remembers me when I took the soldering iron in my hand, the hot part of it.

TLO71 is not rare bird yet, but who knows. I have blown few chips that are no longer available at reasonable cost...

There is good info in geofex.com about protecting effects from reverse polarity, was it under "circuit wrappers" topic or what

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TL072 fries easily?