hi,A.Anand Srinivasan
thank for your helping,but Your idea I , Can I think C1 charge DC voltage set by Votage Divider, And discharge to R4 (load of that circuit). C1 due to R4 as the resistor which value is R4*gain of Q1*gain of Q2.So Time of RC is t=R.C =R4*gain of Q1*gain of Q2*C1.
And If I remove C1 from that Circuit, How will the quality of that circuit change? Because, arcording to my calculation, We can Control voltage output Const depends on range of correlative LOAD without depending on C1 value.