Test Your EQ (Engineering Quotient)

EQ #72

Suppose you know that a nominal 10.000-MHz crystal has a 9.996490-MHz series-resonant frequency and a 10.017730-MHz parallel-resonant frequency. You also know that its equivalent series capacitance is 27.1 fF. How can you calculate the value of its parallel capacitance?

First, calculate the crystal’s equivalent inductance, based on the series-resonant frequency:

Next, calculate the capacitance required to resonate with that inductance at the parallel-resonant frequency:

Finally, calculate the value of CPAR required to give that value of capacitance when in series with CSER:

Note that all three equations can be combined into one, and this reduces to:

Keep up-to-date with our FREE Weekly Newsletter!

Don't miss out on upcoming issues of Circuit Cellar.

Note: We’ve made the Dec 2022 issue of Circuit Cellar available as a free sample issue. In it, you’ll find a rich variety of the kinds of articles and information that exemplify a typical issue of the current magazine.

Would you like to write for Circuit Cellar? We are always accepting articles/posts from the technical community. Get in touch with us and let's discuss your ideas.

Supporting Companies

Upcoming Events

Copyright © KCK Media Corp.
All Rights Reserved

Copyright © 2024 KCK Media Corp.

EQ #72

by Circuit Cellar Staff time to read: <1 min