Do you mean what type or why?
Type: probely ceramic of some sort, NP0 maybe
Why: To create suitable load in order to get stable oscillations
Value: (>5)15-33 pF is normal values
If you change the value you can tune the frequency but you get a worse ocsillator. It's wise to tune as little as possible.
Type: probely ceramic of some sort, NP0 maybe
Why: To create suitable load in order to get stable oscillations
Value: (>5)15-33 pF is normal values
If you change the value you can tune the frequency but you get a worse ocsillator. It's wise to tune as little as possible.
I had a looked in Farnell's catalog.
I don't see NPO ceramics. I can only see ceramic multilayer/disc & palte.
I also had a look at RS online catalog and they don't have NPO ceramic.
Can you please clarify? Thank you. 🙂
Jayel
I don't see NPO ceramics. I can only see ceramic multilayer/disc & palte.
I also had a look at RS online catalog and they don't have NPO ceramic.
Can you please clarify? Thank you. 🙂
Jayel
NP0 (or C0G) is the dielectric, not the physical makup (multilayer/monolithic, etc)
If it is Z5U/X7R/etc it isn't NP0.
If it is Z5U/X7R/etc it isn't NP0.
---------------------------------------------------jarthel said:
Look again at Farnell hard copy. They have moulded ones but are expensive. They also have cheaper dipped ones and COGs
If you need to in a pinch
you can always take two insulated wires, twist together (like a twisted pair) - one inch or less - connect in parallel across the crystal, and make a capacitor for the crystal oscillator. I used to do this to "tweak" the frequency of a crystal by changing the capacitance.
you can always take two insulated wires, twist together (like a twisted pair) - one inch or less - connect in parallel across the crystal, and make a capacitor for the crystal oscillator. I used to do this to "tweak" the frequency of a crystal by changing the capacitance.
That's only good for a few pF. The values he will need a are more likely in the 10-30 pF range.
Jocko
Jocko
Do not change it to X7R, Y5U or anything else than COG or NPO. Anything else to unstable regarding capacitance versus temperature.
Go for the the Values specified by Jocko or PerAnders.
Sonny
Go for the the Values specified by Jocko or PerAnders.
Sonny
Optimum Capacitor Type
As an extension of jarthel's original question - What is the best type of capacitor to use in standard 2 cap/crystal oscillator circuit.
Regards, Eric.
As an extension of jarthel's original question - What is the best type of capacitor to use in standard 2 cap/crystal oscillator circuit.
Regards, Eric.
Based on my question regarding these in several forums, I think you must use an NPO ceramic. There's no other substitute. You may be able to use silver mica? maybe not sure.
Jayel
Jayel
can i used silver mica for clock caps
it is stated in the farnell catalog that the tolerance is 1% compared to the normal clock cap NPO tolerance is 5%
the values are low 10pf
should be better in terms of tolerance to replace the cap rite?
it is stated in the farnell catalog that the tolerance is 1% compared to the normal clock cap NPO tolerance is 5%
the values are low 10pf
should be better in terms of tolerance to replace the cap rite?
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