From: nospam@no-address.com   
      
   On 2018-09-12 18:54, Terry Pinnell wrote:   
   > Is there any consensus on the neatest circuit to take a noisy push   
   > button signal and output a clean rectangular pulse?   
   >   
   > Searching through my ancient (paper) files I found dozens, but my   
   > scribbled notes on many show that when tested I'd found lots failed,   
   > allowing some noise to reach the output. My starting assumption is a   
   > simple CR filter in front of a Schmitt. But before I head for the   
   > shed and start bread boarding I'd much appreciate any recommendations   
   > please.   
   >   
   > Terry, East Grinstead, UK   
      
   The good old 555 timer works nicely in this application. It has a very   
   wide hysteresis (from 2/3 of Vcc to 1/3 of Vcc) that makes the circuit   
   immune to noise and unwanted re-triggers. There is a push-pull logic   
   output available as well as the open-collector "discharge" one, and   
   everything apart from the 3 timing-related passives is integrated. For   
   CMOS logic compatibility from 1.5 V supply and up, there's the LMC555.   
      
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