Reference voltage for lm358

[Murugesh_89]

Hi,
I am connecting a 5.1V zener diode at the inverting terminal of LM358 to use it as a comparator.

When i get a voltage above 5.1 in the non inverting terminal the output need to switch.

I am using 2 lm 358 ic's and uses all the 4 channel as comparator as said above.

My doubt is shall i connect all the inverting terminals of 4 opamp's so that i can use single zener diode or should i have separate zener diodes for reference voltage?

Thanks,
Murugesh

 

[neddie]

How accurate does your reference need to be?
A zener is not going to give you a very accurate reference. It may well be good enough for your
application , don't know. You can connect all the inputs to the same zener , as "theoretically" they don't draw any current.
In practice this is not the case , but the current draw is still pretty small.
Again , all depends on your accuracy required.
Neddie