Methods to generate a single low pulse ?

Thread Starter

Externet

Joined Nov 29, 2005
1,412
A pulse generating circuit senses a DC level increasing from 0V to 5V in about a minute.
When the voltage is increasing and crosses 3V, a momentary low pulse of ~100ms (from +5 to gnd) is desired. --------_---------

A comparator with a capacitive output could do it; can you suggest other methods ?
 

bertus

Joined Apr 5, 2008
20,102
Hello,

As you say you can use a comparator to detect the change over 3 Volts.
This signal can trigger a monostable multivibrator like the cd4047, to make the pulse.

Greetings,
Bertus
 

Thread Starter

Externet

Joined Nov 29, 2005
1,412
Thanks.
Yes, am using a window comparator but the window is detected also when the voltage returns to low, not only when increases.
Miguel
 

SgtWookie

Joined Jul 17, 2007
22,210
When it's triggered on the falling edge, the output will have a positive pulse instead of the negative pulse. You can use a diode to clamp the positive pulse.
 
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