Help with a Oscillator circuit

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furyfax

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I'm using a HC49 crystal in a circuit, which is connected to an IC.
Just wundering is this is correctly designed and what the value of (pF,nF,mF etc) I should have on the output?
I've used **broken link removed** page as help for the design.

I guess this is just to block DC, so I'm thinking of using 10uF(micro), is this OK?
 

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This is my crystal checker circuit. Keep in mind that an overtone crystal will oscillate at the fundamental frequency in this circuit.
 

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But mine will work OK ? I'm not a fan of analog-stuff (sorry), therefore I'm not so skilled in analog design.
 
furyfax said:
But mine will work OK ? I'm not a fan of analog-stuff (sorry), therefore I'm not so skilled in analog design.
Click to expand...

Yes, it should work, but add a bypass cap to the +5v line (1000pF).
 
Russlk said:
No, no, the cap goes to ground. That is the meaning of bypass. What you have is a coupling cap.
Click to expand...
It gives new meaning to the term "DC blocking capacitor".
Of course, it would work if it were a zillion farads, and started out uncharged.
 
It has been my experience with this oscillator circuit that the output frequency will be lower than expected. This is because c27 and c29 are in series with each other but in parallel with the crystal, in this case 60pf which is far greater than the specified load capacitance. The ratio of those two capacitors also determines the feedback for osillations. The way around it is to put a small capacitor in series with the crystal, so the combined capacitance of the series capacitor and c27 and c29 = the load capacitance of the crystal.
 
Please post the schematic including the IC. It's possible that the IC doesn't require a separate oscillator, you can probab;y just add a couple of capacitors and a crystal and it will work.
 
Here's the whole schematic. It is not finnished at all. A lot of works remains.
The oschillator circuit is at the left, and is connected to pin 3 on the AD725.
 

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