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square wave voltage level changing

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aliraza786

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hello i have a ir sensor which gives out in the range from 4.5 to 3.5 but i want to change the level of thet square wave from o to 5 volts kindly guide me in this problem thanks
 

Show your output stage "which gives out in the range from 4.5 to 3.5",
and your load which should receive "that square wave from o to 5 volts"!
 
when nothing is in front of sensor there is a volatge 4.5 and when something come in front it give pulse which goes from 4.5 to 3.5 and then come back to 4.5,, i want this pulse 0 at the place of 3.5 and 5 at the place of 4.5 or u can say that i just want to change 3.5 to 0,, 4.5 is ok...

load is almost 10mA not more then this
 

I'd use a CMOS comparator like, e.g. LMC7211, supply it with 5 .. 5.5V and set the trigger level at 4V.
 

thanks for your reply.....using comparator was also a option in my mind but i have learnt that in using comparator there is a chatter at the edge when comparator output goes from high to low or low to high... which gives unwanted pulses.. which i cannot afford because the output pulses will count and decision will be make on the basis of amount of pulses..
 

aliraza786 said:
... i have learnt that in using comparator there is a chatter at the edge when comparator output goes from high to low or low to high... which gives unwanted pulses ...
Click to expand...

Right. You have to insert some hysteresis: a few percent of positive feedback.
 

You need a schmitt-trigger. You can build one with a simple op-amp and a few resistors. This way you can set freely your trigger levels at any voltage you want.
 

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