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Suresh R
02/15/06 03:59
Read: 566 times
Chennai
India


 
#110025 - followups & Back EMF's?
Responding to: Kai Klaas's previous message
Kai Klaas said:

By this, voltage dropping across Pot R6 increases and more and more current of the 10mA current is flowing through it. But across R8 voltage drop remains constant, about 0.7V, so far.

It is said that R7 is fixed and holds the voltage accross the o/p and adj terminal (1.24V). So by putting R7 = 120V/.25W will dissipate all power in it.
If this is the case, how could Q4 (emitter pin) receive voltage to drive the major part of the 10mA current through it.

Kai Klaas said:

Take care, also Q2 might need cooling!

yes.

Protection diodes:
i could see a circuit in data sheet having protection diode (also one (D6)in the circuit i have posted) to avoid the effect of cap (connected at o/p) discharge through low current path.
i would like to know how the diode nature helps to avoid this current flow.

Back EMF:
I have also come accross the use of diodes to prevent back EMF from coils.
How does a diode help in overcoming these problems.

-suresh.


List of 21 messages in thread
TopicAuthorDate
3A constant current source      Suresh R      02/11/06 04:41      
   Where did you find it?      Andy Neil      02/11/06 05:56      
   Ripple      Andy Neil      02/11/06 06:00      
      plating purpose      Suresh R      02/11/06 09:45      
         I got it from a person known to me      Andy Neil      02/11/06 15:04      
            replies      Suresh R      02/12/06 09:24      
               plating circuit      Terry Lingle      02/12/06 11:40      
                  Compliance of source      Steve M. Taylor      02/12/06 13:51      
                     yes      Terry Lingle      02/12/06 16:21      
         Think about that      Neil Kurzman      02/11/06 16:08      
   Component Purposes      Bruce Bailey      02/11/06 12:58      
   This circuit will never work!      Kai Klaas      02/11/06 19:46      
      Could it be?      Neil Kurzman      02/11/06 23:55      
         Function      Kai Klaas      02/12/06 20:08      
            issues      Suresh R      02/13/06 02:42      
                plating quality control.      Terry Lingle      02/13/06 07:29      
               Answers      Kai Klaas      02/13/06 11:36      
                  followups      Suresh R      02/14/06 02:20      
                     Answers II      Kai Klaas      02/14/06 07:01      
                        followups & Back EMF's?      Suresh R      02/15/06 03:59      
                           Floating regulator      Kai Klaas      02/15/06 09:27      

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