LM358 Test circuit

Thread Starter

Ford Prefect

Joined Jun 14, 2010
193
Hi guys,

I tend to use quite a few LM358's in several of my circuits but I have come across some LM358's which have been faulty.
I have soldered them into my circuits and after discovered that the LM358 is at fault then have the annoying task of unsoldering the LM358 and replacing it with another LM358.

I have been thinking to build an LM358 test circuit so that I can quickly plug in the LM358 into an IC socket and checking if it is faulty or not...but have not been very successful.
Can someone come up with some ideas and a suitable (and good) LM358 test circuit so that I can test both sides of the amp maybe with some LED's etc.

Thanks a lot.
 
Last edited:

Delta prime

Joined Nov 15, 2019
430
Do not solder the lm358 just keep it in the socket of your designs.Given the performance of a lm358 I think a socket is in order.
1595940361953.png
I have also seen a lot of circuits concerning go no-go test for operational amplifiers. Duals, Quads you'll be surprised you can pick one out and post it I could check the circuit for you to see if it will fly.:)
 

OBW0549

Joined Mar 2, 2015
3,506
Can someone come up with some ideas and a suitable (and good) LM358 test circuit so that I can test both sides of the amp maybe with some LED's etc.
How elaborate a circuit you need will depend entirely on how much you want to test.

If you want to accurately characterize the various op amp parameters (input offset voltage, input bias current, DC open-loop gain, gain-bandwidth product, output voltage swing, etc, etc) that will be quite a task.

On the other hand, if all you want is a quick go/no-go test that will verify the op amp's basic functionality, then the easiest thing I can think of is a simple oscillator circuit:

lm358.png
If you change R1 to 470 kΩ and C to 1.0 μF and connect an LED and appropriate series resistor to the op amp's output, you should see the LED blink on and off at about a 1 Hz rate.

You'll need two of these circuits, one for each side of the LM358.
 

Thread Starter

Ford Prefect

Joined Jun 14, 2010
193
How elaborate a circuit you need will depend entirely on how much you want to test
On the other hand, if all you want is a quick go/no-go test that will verify the op amp's basic functionality, then the easiest thing I can think of is a simple oscillator circuit:

View attachment 213354
If you change R1 to 470 kΩ and C to 1.0 μF and connect an LED and appropriate series resistor to the op amp's output, you should see the LED blink on and off at about a 1 Hz rate.

You'll need two of these circuits, one for each side of the LM358.
Yes, thanks OBW0549, this is a good idea
I do not want anything too elaborate just a simple go/no-go test circuit to test each side of the op amp independently. I may try this
I may even increase R4 to something like 220k to reduce the hysterisis.
I had a LM358 a few weeks ago and tested it with a multimeter, one side was ok but the other side was faulty.
I wonder if someone else can come up with another good circuit
 
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AnalogKid

Joined Aug 1, 2013
8,536
First pass at an analog gain test circuit. All resistors can be 5% tolerance. C1 should be located as close as possible to pins 4 and 8. The indicated output voltages are based on a diode forward voltage of 0.6 V. This will vary because of the diode forward voltage at such a low current. Verify the circuit with known-good parts, and use those output voltage values for future testing.

ak
LM358-Test-1-c.gif
 
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Thread Starter

Ford Prefect

Joined Jun 14, 2010
193
First pass at an analog gain test circuit. All resistors can be 5% tolerance. C1 should be located as close as possible to pins 4 and 8. The indicated output voltages are based on a diode forward voltage of 0.6 V. This will vary because of the diode forward voltage at such a low current. Verify the circuit with known-good parts, and use those output voltage values for future testing.

ak
View attachment 213388
Thanks AnalogKid
I shall study and have a closer look this..
 

Thread Starter

Ford Prefect

Joined Jun 14, 2010
193
How did you determine that one side was good and one was bad? Does side mean opamp? Or opamp input?
Why do you want something else?
dl324, I just had a look at this video a few weeks ago...
I tested one half of an LM358 (pins 1,2 and 3) which gave good results. The other half (side) (pins 5, 6 and 7) gave very low and strange results to which I thought the Op-amp must be faulty.
 

dl324

Joined Mar 30, 2015
11,264
I tested one half of an LM358 (pins 1,2 and 3) which gave good results. The other half (side) (pins 5, 6 and 7) gave very low and strange results to which I thought the Op-amp must be faulty.
Could you summarize what the video showed? I got bored after 5 seconds.

With a DVM, you can check the collector-base junction on the input transistors (Q1 and Q4). You can't check anything about the output.

From a Nat Semi datasheet:
clipimage.jpg
 

Audioguru again

Joined Oct 21, 2019
1,757
American and European opamps bought in North America or Europe are extremely reliable. Did you buy cheap fakes from ebay, Amazoom, Aliwhatever or Bangbad?
 

Audioguru again

Joined Oct 21, 2019
1,757
The Video from the student in India (again and again these videos come) did not test the opamps. Instead it tested the collector-base diodes of the inputs and outputs.
I do not know the language that was spoken.
 

OBW0549

Joined Mar 2, 2015
3,506
dl324, I just had a look at this video a few weeks ago...
I tested one half of an LM358 (pins 1,2 and 3) which gave good results. The other half (side) (pins 5, 6 and 7) gave very low and strange results to which I thought the Op-amp must be faulty.
Don't ever attempt to test a complex IC like an op amp using only a DVM; your "test" shows nothing.

Also, be very, VERY careful when trying to get electronics information from YouTube videos; with very few exceptions they are created by ignorant idiots and the only thing you'll learn from them is superstitious nonsense.
 

Thread Starter

Ford Prefect

Joined Jun 14, 2010
193
Don't ever attempt to test a complex IC like an op amp using only a DVM; your "test" shows nothing.

Also, be very, VERY careful when trying to get electronics information from YouTube videos; with very few exceptions they are created by ignorant idiots and the only thing you'll learn from them is superstitious nonsense.
Thanks I really know this but I found that trying this resulted in an apparent faulty IC, this is why I want and asked for a simple, quick test circuit so I can definitely prove if the IC is a go / no-go.
 

Thread Starter

Ford Prefect

Joined Jun 14, 2010
193
American and European opamps bought in North America or Europe are extremely reliable. Did you buy cheap fakes from ebay, Amazoom, Aliwhatever or Bangbad?
I suppose it does not really matter where the components came from even if you were to source them from a shop or supplier in an American or European country. Can you absolutely guarantee that the components didn't originate from a cheapo supplier!
 

Papabravo

Joined Feb 24, 2006
14,241
I suppose it does not really matter where the components came from even if you were to source them from a shop or supplier in an American or European country. Can you absolutely guarantee that the components didn't originate from a cheapo supplier!
Tell us who you plan to buy from and why. We will tell you if we know of any reason why you should or should not do business with them. What kind of quantities are we talking about?
 

Thread Starter

Ford Prefect

Joined Jun 14, 2010
193
Can we please all get back to the question of a design for an LM358 test circuit?
With everyone starting to talk about authentic parts and authorised dealers this post is completely going off the subject.
 

OBW0549

Joined Mar 2, 2015
3,506
Can we please all get back to the question of a design for an LM358 test circuit?
So far you've got three suggestions for a test circuit; all of them will do the job, and I can't think of anything simpler that will do a meaningful test. Are these three circuits inadequate in some way? And if so, what's wrong with them?
 
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