555 timer frequency problem

[rakirajueee08]

can i change the frequency of a astable multivibrator circuit of 555 timer by selecting the R1,R2,C? ineed two mhz signal ?for this 2 mhz frequency which values of resistance i can pick up if i use c=0.1 uf?

 

[AdvaRes]

Hi,
You can find a lot of tools for you calculation on the www:

http://www.ohmslawcalculator.com/555_astable.php
http://www.buildcircuit.com/free-555-timer-simulator-for-electronics-beginners/

Advares

 

[amayilsamy]

You Can use. R1= 3.3 K R2= 1.8K , C=0.1 nF. OR R1= 2.2 K R2= 1.2K , C=0.1 nF.

If C=0.1 uF. It is difficult generate 2 MHz.

I hope Its helps you.

 

[rakirajueee08]

you said that it is difficult to generate 2 mhz.but your parameter gives 3.137 mhz.will it be stable and good working.

 

[amayilsamy]

Sorry . I made made a mistake . In Second perameter R2 value is 2.5 K.

First one is 2.08 MHz.

 

[oufuqiang]

ne555 maximum operating frequency is only 100KHz.
Why not use a crystal oscillator?