555 voltage controlled oscillators

[myfaithnka]

Hi all,

is there any way we can work the 555 VCO such that its frequency increases when input voltage decreases ?

thanks.

 

[E-design]

Just invert the VCO input control voltage using an op-amp.

 

[rahdirs]

Hi all,
is there any way we can work the 555 VCO such that its frequency increases when input voltage decreases ?

Didn't you have a similar thread:https://www.edaboard.com/threads/291139/
Why start a new thread when that thread is only 15 days old ????

Did you try to use a logarthmic amplifier along with antilog amplifier.
Thus 1/V = antilog(log(1) + (-(log(V))).
Often the results may need to be scaled to fit in the voltage range