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[SOLVED] Timer circuit architecture

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kenambo

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I have read NE 555 timer circuit datasheet. How the internal flip-flop on/off the Discharge transistor. And in monostable mode of operation what is the significance of the capacitor charging and discharging.
 

Hi dear kenambo*
At first : 555 is very useful !
If you want turned on the transistor of discharge , pin 6 (THRSH) must be more than 2/3 Vcc.
and for turned off the transistor , pin 2 (TRIG) must be less than 1/3 Vcc .
I hope it be useful for you.

Best wishes
Green tree
 

Thanks greentree. I have another question for you that is what is the importance of the discharge transistor regarding timer operation. Please answer it. Thank you again.
 

While a monostable does not give a continuous train of pulses, after charging the capacitor and giving a single pulse it needs to discharge the capacitor so it is ready to produce another pulse other wise it could only ever give one pulse.

Keith
 
Hi dear kenambo*
The discharge transistor determine time of off . if this transistor be on , your capacitor falling to the 1/3Vcc .when transistor is on until it be off is time of off. you can manage this time very simple .
if the discharge transistor didn't on you have just a high voltage always because your capacitor can't discharge so always out is high . you can see this example :
aa-555-slow.gif

I will give you a gift !
With this circuit you can determine time of off and time of on . please think about it my friend.
555.JPG

Best wishes
Green tree
 
Hi green tree, thank you very much for ur gif file.
 

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