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LM311

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be80be

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What do with the BALANCE and strobe then the strobe is low the chip is off so I pull it high.
With a resistor but a can't seem to find anything showing how to use them.
 

ronsimpson

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don't connect to balance and strobe. The will work no connect.

Please show how you connected pins 8,7,1,4.
The output(s) is/are complicated and probably the problem is there.
 

be80be

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I never used it before but I posted in post one that it said if the strobe is low the chip is off and nothing about the BALANCE
it works with them floating. i just trying to figure how to use them.

LM311circuit.png
 

alec_t

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The balance and strobe pins can be used for offset-nulling, e.g. by connecting them respectively to the two ends of a (250k or so) pot, with the pot wiper connected to the +ve rail.
 

crutschow

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Look at Figure 17 in the data sheet.
 

spec

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The LM311 was one of the first high speed comparators to be introduced way back in the 1970s. It has a response time an order faster (165nS) than the other early common comparators, the LM393 (dual) and LM339 (quad) (1.3uS).
LM311 data sheet: http://www.ti.com/lit/ds/symlink/lm311.pdf
LM393 data sheet: http://www.ti.com/lit/ds/symlink/lm2903-n.pdf
LM339 data sheet: http://www.ti.com/lit/ds/symlink/lm2901-n.pdf

While the LM311 is a very useful chip, it can misbehave if great care is not taken with the circuit design and physical layout: http://www.ti.com/lit/an/snoa860/snoa860.pdf

Sorry to be a doom monger.

spec

(PS: it is odd that the data sheet describes the LM311 as a quad comparator when in fact it is only a single. Over the years I have written to National Semiconductor and subsequently Texas Instruments about this but have never got a reply- am I missing something?)
 
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