thank you very much of all for helping me..and i am very glade for helping me, fvm. but sir i have connected potentiometer with pin 6 of 1kohm , when i set the value of potentiometer to minimum (mean zero) then frequency is 400khz and by increasing the value of potentiometer the frequency increases more ,which is not my required frequency , my required frequency is 20khz .so please suggest me the circuit for 20khz to generate. i have uploaded the circuit diagram i am using . if any error is there in my circuit please tell me about that . thankssssss.....