[sdiy] Trigger To Gate Circuit

[Tom Wiltshire]

Bill,

Dave is right to wonder what makes the gate go low. Trigger only  
indicates the start, not the end.

However, if you're just looking to turn brief trigger pulses into  
longer 'gate' pulses (a trigger width stretcher), then you could  
probably just use the trigger pulses to trigger a basic monostable  
like the venerable 555 timer. I use the CMOS version when I use it  
because it doesn't cause such nasty glitches on the power rails.
You'll find a million 555 monostable circuits on the web, I'm sure.

T.

On 7 Jun 2008, at 15:50, David Brown wrote:

> I did a trigger delay using a CD4538.   Details of my trigger delay  
> is at http://modularsynthesis.com/modules/DJB-008/djb008.htm
>
> I'm not sure about the trigger to gate.  What makes the gate go  
> low?  Are talking about a trigger width stretcher?  The Q output of  
> the first monostable (pin 10) is a stretched trigger.  It triggers  
> the second monostable on the falling edge to generate a 5 mS  
> trigger.  You could get two trigger stretchers out of the same part  
> by just using the first part of the schematic.  You can eliminate  
> the gate circuitry and just tie the resets high.  I made the  
> monostable trigger on the falling edge but you could use the +  
> input to make it trigger on the rising edge.
>
> Dave
>
> At 07:50 AM 6/7/2008, Eyesaw wrote:
>> Hello - I have a need for a circuit to convert triggers to gates.  
>> A trigger delay will work, I believe. Wondering if anyone knows a  
>> schematic or can describe a design to address this issue?
>>
>> Thanks for your help -
>>
>> Bill
>
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