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Suresh R
03/01/06 03:37
Read: 647 times
Chennai
India


 
#110962 - analysis results
Responding to: Kai Klaas's previous message
Kai Klaas said:

Try to find out how the circuit works - by yourself. Make an analysis of the circuit and post your results here. And - you should at least spend as much time as I did...
Kai


This is what i got from the circuit.

Kindly let me know about the mistakes i have done:

Trigger input connection:

The 10k and 1uF forms a differentiator network which delivers positive and negative going spikes.
The diode is used to limit the amplitude (by becoming frwd biased) at trigger i/p to .7V during the positive going spike.
This .7V flow to the RC network 1K / 10nF.( - Kindly give me few info to know the use of this RC network)

Reset pin connection:

The reset pin is also connected with a similar difftr network with voltage limiting diode. Here the reset pin receives .7V (typical value for device reset when current through it is .1mA)

- I need to know how the flow of current through the reset pin is calculated when using such RC network.
Is just applying ohms law enough = V (source vol) = I*220K
I = 5 / 220K (Since current through cap decreases with increase in its charge )

Comments needed.

Lastly regarding that transistor Bc550,
i could only find that it will be 'ON' for the time delay i will be setting with the Pot.

when the SW is depressed continuously:

Also referring to the abnormality curves (that happens when the SW is depressed continuously) discussed before, i could only take it in a way that 'the Transistor is doing the same job as that of the switch (either one is going to ground the cap) connected parallel to it when the Switch is depressed continuously..
So iam unable to come to a conclusion on how it rectifies the problem of abnormality.

giving some hints could help me know about it.

Thanking u,
suresh.


List of 39 messages in thread
TopicAuthorDate
Pressing 555 trigger SW continuously.      Suresh R      02/24/06 03:57      
   Again      Andy Neil      02/24/06 04:38      
   capacitor couple it.      Steve M. Taylor      02/24/06 10:34      
      Re: cap coupling      Suresh R      02/24/06 23:37      
         Look up the internal block diagram      Kalpak Dabir      02/24/06 23:51      
            Read the Data Sheet!!      Andy Neil      02/25/06 03:17      
      got the o/p      Suresh R      02/25/06 03:59      
         Satisfaction      Steve M. Taylor      02/25/06 04:08      
            Thanku steve      Suresh R      02/25/06 04:33      
         Not enough      Kai Klaas      02/25/06 07:33      
            alternatives ?      Suresh R      02/26/06 22:01      
               Remedy      Kai Klaas      02/27/06 19:16      
                  remedy?      Andy Neil      02/28/06 01:04      
                     Alternatives      Kai Klaas      02/28/06 06:56      
                  BC550 & diodes      Suresh R      02/28/06 04:34      
                     Try it by yourself, it's simple!      Kai Klaas      02/28/06 06:47      
                        analysis results      Suresh R      03/01/06 03:37      
                           Analysis      Kai Klaas      03/01/06 20:14      
                              Thank you      Suresh R      03/01/06 23:10      
                              after the set delay Time      Suresh R      03/02/06 02:07      
                                 Enhanced debouncing      Kai Klaas      03/02/06 10:03      
                                    What do you think about it, Suresh?      Kai Klaas      03/06/06 17:55      
   why the neqw thread      Erik Malund      02/24/06 10:55      
      reply      Suresh R      02/24/06 23:20      
         Read the Data Sheet!!      Andy Neil      02/25/06 03:16      
   kalpak dabir      Satish S Munot      02/25/06 00:52      
   Have you considered using a 74121?      Richard Erlacher      03/04/06 15:18      
      74121 versus CMOS555      Kai Klaas      03/05/06 06:53      
      74121 fine for short period delays?      Suresh R      03/07/06 06:03      
         No debounce needed???      Kai Klaas      03/07/06 06:33      
            Schmitt trigger operation?      Suresh R      03/08/06 05:41      
               Transition times of input signal      Kai Klaas      03/08/06 09:21      
                  controlling noise related issues      Suresh R      03/11/06 04:08      
                     Schmitt-trigger operation      Kai Klaas      03/11/06 06:48      
                      CD 4541BC = Alternative for ICM 7555?      Suresh R      03/22/06 04:52      
                        Do you really need to build it?      Kai Klaas      03/23/06 06:40      
                           Yes.      Suresh R      03/23/06 08:38      
                              try try try again      Steve M. Taylor      03/23/06 09:22      
                                 a sign of confidence      Suresh R      03/23/06 09:59      

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