View Full Version : 89c2051 taking >2v as logic 1

01-29-2009, 01:03 AM
hi friends,
im doin a line follower bot.
i hav 2 doubts.
my comparator output voltage when sensors blocked and unblocked are 3.7v and 2v.

these two are given as inputs to my 89c2051 controller.

the problem here is controller taking both 3.7v and 2v as logic1..

how to reduce the output voltage of comparator from 2v to 0?


how to make controller to take 2v as logic 0?

hope u l do clarify my doubt..


01-29-2009, 01:02 PM
which comparator are you using?

Comparators give discreet high and low as outputs. If you are using LM 311 or 339, you have to add a pull up.

If you are using op amps, you just have to get the design right.