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7404 Hex inverter stuck on 2.5v

evilmorty

Apr 14, 2016
3
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Apr 14, 2016
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Hi,

I got a problem with the hex inverter. The idea is to clearly define the pulses coming in from a few optical encoders working on phototransistors, but I'm having a problem where 7404 output suddenly settles to around 2.5v.
Would anyone have any guidance on how i can fix this issue?

Many thanks
Morty
 

evilmorty

Apr 14, 2016
3
Joined
Apr 14, 2016
Messages
3
It's basic I don't have any external components such as pull up/down resistors
image.jpg

The inverter outputs will go into the MCU or a LS7084 clock converter that will take the A and B channels and make one pulse. I've yet to get to that stage to decide what will work best
 
Last edited:

Alec_t

Jul 7, 2015
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Jul 7, 2015
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I'm having a problem where 7404 output suddenly settles to around 2.5v.
Have you checked that with a 'scope? If the output were oscillating and you checked with a DMM, 2.5V would be a reasonable measurement.
 

Alec_t

Jul 7, 2015
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Jul 7, 2015
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Have you left any of the unused inverter inputs floating? That might produce weird results.
 

Colin Mitchell

Aug 31, 2014
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Aug 31, 2014
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Take everything off the chip and put 1k between input and 5v rail. What is the output ?
Put 1k between input and 0v rail. What is the output ?
 
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