LM358 problem

Thread Starter

hazim

Joined Jan 3, 2008
435
Hello,
I'm using one side of LM358N as a comparator. A voltage divider using a photoresistor and a resistor connected at the inverting input, and a trimmer potentiometer at the non-inverting input. The datasheet says that Vcc can be as low as 3V. In my circuit Vcc=4V, and the output is 2.8V when high. I thought the IC is corrupted so I used another one... but it's the same. Is this normal since the supply voltage is low(4V)?
 

SgtWookie

Joined Jul 17, 2007
22,230

Thread Starter

hazim

Joined Jan 3, 2008
435
I have read the datasheet of the IC from onsemi. What I notice after I reviewed it is that at Vcc=5V and RL=2K, VOH min is 3.3V. I can compare the values in this case to mine but there is no affirmed accurate values I know...
Thank you
 

Thread Starter

hazim

Joined Jan 3, 2008
435
3.5V
Where to find the electrical characteristic differences between LM358A and LM358N? if there is any or this suffix refers to the package only?
 

SgtWookie

Joined Jul 17, 2007
22,230

SgtWookie

Joined Jul 17, 2007
22,230
Just for clarification:
LM358 - basic part number.
LM358A - An improved version of the basic part.
N - a package suffix for either the LM358 or LM358A
 

Thread Starter

hazim

Joined Jan 3, 2008
435
1- I love electronics
2- I love datasheets!
3- I always read datasheets
4- I read the onsemi and the national datasheets of LM358
5- I confess that I don't understand everything in the many datasheets, but I want to learn what I don't know.
Again, I really like to read datasheets, believe or don't believe :)

Best regards,
Hazim
 

Audioguru

Joined Dec 20, 2007
11,248
When I was a nOOb, I had the Philips, Signetics and Motorola databooks.
Then I moved and my next door neigbour worked for Fairchild and gave me lots of datasheets and application notes.
 
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