Author Topic: Why is my Op Amp smoking?  (Read 1058 times)

groovy_guy

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Why is my Op Amp smoking?
« on: July 02, 2023, 04:23:34 AM »
Hi I'm wondering if anyone can help me figure out what is wrong here. I recently built a dual buffer using the Klon buffer schematic. I used the TL072 to build 2x buffers in 1. When I connect the power (DC 9V) it starts to smoke. I'm pretty sure it's coming from the op amp but not certain. This happened the first time when the board was in the enclosure so I thought maybe something was touching the enclosure that shouldn't have been and causing a short. But I tried it on a second build without placing it in an enclosure and the same thing happened. I have attached my schematic. If anyone could spot any mistakes that would be appreciated. Otherwise I must have a short on the board somewhere that I haven't been able to spot.

Thanks

madbean

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Re: Why is my Op Amp smoking?
« Reply #1 on: July 02, 2023, 05:39:16 AM »
Your schematic looks fine. Smoking amp likely means too much current is being pulled. This could be from a shorted polarity protection diode or shorted decoupling caps on v+ or vb.

groovy_guy

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Re: Why is my Op Amp smoking?
« Reply #2 on: July 03, 2023, 04:20:47 AM »
Thanks for the advice. I finally worked out the issue. I bloody used 10k resistors instead of 100k for R5 and R9! Swapped them out and it now works perfectly with no smoke :)

mjg

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Re: Why is my Op Amp smoking?
« Reply #3 on: July 03, 2023, 03:48:22 PM »
I was going to suggest peer pressure, because it thought it would make it look cool?  But yeah, the resistors might do it too  ;)

gordo

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Re: Why is my Op Amp smoking?
« Reply #4 on: July 03, 2023, 05:53:46 PM »
It starts off with one or two and before you know it they're up to a pack a day.  :-)

Glad you got this sorted out.  In a recent build I mistook a NE5532 for a NE555 (ones an audio amp, the other a timer).  Not only did the transistor get hot but I touched the metal back plane (smooth move on my part) and it branded one of my fingers.
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jimilee

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Re: Why is my Op Amp smoking?
« Reply #5 on: July 03, 2023, 05:58:39 PM »
It starts off with one or two and before you know it they're up to a pack a day.  :-)


I blame the parents.


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JackSkellington

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Re: Why is my Op Amp smoking?
« Reply #6 on: July 04, 2023, 02:09:17 AM »
Thanks for the advice. I finally worked out the issue. I bloody used 10k resistors instead of 100k for R5 and R9! Swapped them out and it now works perfectly with no smoke :)

Excuse me, but why 10k resistors to the ground before the output make your op-amp smoke? It doesn't seem to me something so bad, or I wrong?
«Just because I cannot see it doesn't mean I can't believe it»

groovy_guy

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Re: Why is my Op Amp smoking?
« Reply #7 on: July 06, 2023, 01:36:57 AM »
Thanks for the advice. I finally worked out the issue. I bloody used 10k resistors instead of 100k for R5 and R9! Swapped them out and it now works perfectly with no smoke :)

Excuse me, but why 10k resistors to the ground before the output make your op-amp smoke? It doesn't seem to me something so bad, or I wrong?

I have no idea! But I don’t question it. All I know is it works now ¯\_(ツ)_/¯

groovy_guy

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Re: Why is my Op Amp smoking?
« Reply #8 on: July 06, 2023, 01:38:25 AM »
I was going to suggest peer pressure, because it thought it would make it look cool?  But yeah, the resistors might do it too  ;)

Now I feel like a ciggy. This TL072 is a bad influence 😤
« Last Edit: July 06, 2023, 04:18:41 AM by groovy_guy »

bluelagoon

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Re: Why is my Op Amp smoking?
« Reply #9 on: July 10, 2023, 09:21:50 AM »
Probably smoking cause did not read the Surgeon Generals warning on the pack of cigarettes

jwin615

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Re: Why is my Op Amp smoking?
« Reply #10 on: July 10, 2023, 08:20:45 PM »
Probably smoking cause did not read the Surgeon Generals warning on the pack of cigarettes
Everyone knows opampa can't read. They just repeat what they've heard before. In one ear, out the other.