Floppy disk drive STEP signal driving a LED

• Floppy disk drive STEP signal driving a LED
  Posted by caius on 17 Dec, 2022 23:55
• Hi all,
  I'm trying to drive a LED by the STEP signal (active LOW) of a floppy drive but LED lit briefly when single pulse occur.Do I need to a stretching circuit, perhaps?Can you advice me some solution?Thanks in advance.
• #1 Reply
  Posted by retiredfeline on 18 Dec, 2022 02:08
• Yeah you need a monostable. Lots of designs around of which fer shure they'll be a 555 one.
• #2 Reply
  Posted by Stray Electron on 18 Dec, 2022 02:52
•   All you need is a simply Logic Probe circuit.  There should be plenty of circuit designs available online.
• #3 Reply
  Posted by caius on 18 Dec, 2022 11:17
• Thanks for replies.
  The STEP pulse is around 7us as measured by a logic analyzer :
  
  
  
  
  I have in mind the attached designs (without 555 for now), which could be the more appropriate? (RC value must be adapted obviously)
  
  
  
  

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