555 connections for monostable

Thread Starter

denison

Joined Oct 13, 2018
312
Hi, I have a circuit for monostable operation of a 555 for a low going input pulse to a timed high output pulse.
Can anybody provide the circuit for the opposite. For a high going input pulse to a timed low output pulse. Only need very brief, in order of us, output pulse determined of course by the capacitor.
 

Papabravo

Joined Feb 24, 2006
19,570
Hi, I have a circuit for monostable operation of a 555 for a low going input pulse to a timed high output pulse.
Can anybody provide the circuit for the opposite. For a high going input pulse to a timed low output pulse. Only need very brief, in order of us, output pulse determined of course by the capacitor.
Using an inverter is the easiest way to solve the problem. You can do this with a single transistor. How about a schematic of what you have.
 

Ian0

Joined Aug 7, 2020
6,677
F013581E-73AD-48A2-86F2-ADD25B9E4FCD.jpegSwap over pins 2 and 6. You then need a positive-going version of Discharge, which you can implement with a diode from the output.
THere will be a slight reduction in timing accuracy on low supply voltages because the capacitor is not fully discharged.
 
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