[R-390] Some Crystal Info

[Tony Casorso]

Hi everybody. Sorry that my image thread got so long. I'm still looking at the problem but I'll keep the details to myself and only post here if I make some headway.

For a while now I've been wondering what the difference between a CR36/U and a CR27/U crystal was. I found a reference to them in an old paper that is only available to paying members of IEEE. I believe the paper is from the 1950s as it is full of tube oscillator circuits. I started a new job in July and it turns out that I have access to all of the IEEE papers. This one is called "Design Data for Crystal Oscillators" By H.E. Gruen of the Armour Research Foundation. It says that the CR18/U, CR27/U, and CR36/U crystals are all designed for 32pf loads to be used in parallel resonant mode (antiresonant mode in the paper). The difference between them is that the CR18/U is not for use in ovens while the CR27/U is for oven applications at 75 degrees C and the CR36/U is for oven applications at 85 degrees C.

Hopefully someone will find this information useful.

Cheers,

Tony