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need some advice about the lm555

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MikeMl

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A stable capacitor: Silver mica, mylar, polystyrene, etc
 

bountyhunter

Well-Known Member
does anyone know whats the best capacitor to use with the lm55 in creating the oscillator?
You didn't specify exactly how accurate the frequency needs to be.
A ceramic cap with X5R or X7R dielectric type is very good for stability and initial tolerance and is way cheaper (and smaller physical size).
 
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tuan_101

New Member
haha no im not trying to scare off animal, im trying to build a walking stick for the blind that has a sensor on it, so when the stick approaches an object thats close it will generate a sound through an amplifier. i am aware that the guide dog might be annoyed with it and go insane.

sorry for not specificing the stability of the frequency. the the frequency range is -+5% of the 40khz, so thats 38KHZ< X < 40KHZ. i have thought of using electrolytic, but i was told by someone that it would not do the job at all

i have another question though, would this oscillator drift? as in its not very stable with the 555?
 
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MikeMl

Well-Known Member
Most Helpful Member
Using good metal film resistors, and a good capacitor, it will be stable enough, especially if the 555 runs on a regulated supply.
 
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