Here they are sorry. I added the revision suggested by SgtWookie.

John

 

Thanks, John!

I will save it locally.

 

Do you have an accurate frequency counter? I only built the circuit on a breadboard and fear that a real PCB design would require a different capacitance. As you know, the capacitance loading can pull the frequency in either direction. If too much, the freq will be slightly low; too little it will be high.

If you have a CMOS 555, it might be worth a try. Maybe I will try it after breakfast.

Edit: Breakfast will wait. Yes, the CMOS 555 works much better. It starts right up and has a nice square wave without the little hump. Uses same capacitance as the NE555 on the breadboard.

John

Hi John, can you share the original 555 crystal oscillator schematic with me? Thanks......Fred

 

jpanhalt has not been here for two years. There are many well-understood ways to drive a crystal.