Other Parts Discussed in Thread: LM2903
1.> The application Circuit as enclosed schematic.
2.> test condition:
a.) Power supply 5V to LM2903's pin8 ( Vcc )
b.) LM2903's pin 3 ( Comparator 1's positive input pin ) connect to 4.5V(target voltage)
c.) LM2903's pin 2 ( Comparator 1's negative input pin) connect to Analog input signal from 2.5v ~ 5v
d.) LM2903's pin 1 ( Comparator 1's output pin ) pulled high to 5V with 1k ohm
3.> issue Description :
The LM2903's pin 1 ( Comparator 1's output pin ) should turn from High to Low when LM2903's pin 2 ( Comparator 1's negative input pin) reach
the voltage(4.5v) of LM2903's pin 3 ( Comparator 1's positive input pin ) , actually as my testing condition , The LM2903's pin 1 ( Comparator 1's output pin )
turn from High to Low when LM2903's pin 2 ( Comparator 1's negative input pin) reach 3.9v , it (LM2903's pin 2) has not reach 4.5v yet !! why ??
Even I change LM2903's pin 3 to 2.83v , and let LM2903's pin 2 from 0 to 3v , the result is the same , Before LM2903's pin 2 reach target voltage ( 2.83v )
in fact LM2903's pin 2 at 2.75v , LM2903's pin 1 ( Comparator 1's output pin ) turn to Low .
