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T O P I C R E V I E W
kivdenn
Posted - Dec 15 2009 : 09:23:45 AM Are the functions of an opamp IC such as LM358 and voltage comparator IC such as LM393 the same, I mean do the two serve the same purpose ? Bse I have a project which uses LM358 but its cost is more than that of LM393, is it possible to use LM393 in place of LM358? Also I have a circuit which requires two LM741 opamp IC bse it is a single opamp IC and I would like to use one dual opamp IC, can LM393 still serve my purpose? Thanks Dennis
1 L A T E S T R E P L I E S (Newest First)
audioguru
Posted - Dec 15 2009 : 10:10:08 AM The output of an opamp goes high and goes low. But the output of a comparator is just the collector of an NPN transistor that can only go low. A pullup resistor causes it to go high. Then comparator outputs can be connected togeter and one or more than one can cause their combined outputs to go low.
An opamp is able to use negative feedback but a comparator normally cannot use negative feedback.
The 741 opamp is 42 years old and has poor performance. The LM358 dual opamp is slightly newer but because it was the first low power opamp (and the LM324 quad opamp is the same) then its performance is also poor.