0

Troubleshooting a 32kHz Crystal Oscillator – How to Actually Make it Oscillate? #hamr

xtal_osc_spice_model

Now for an oscillator to work, we need an amplifier with a gain of greater than 1, and a phase shift of 360 degrees to get positive feedback.

First problem – the transistor was saturated, with Vc stuck near 0V. For an oscillator to start noise gets amplified, filtered by the crystal, amplified again etc. I reasoned that if the amplifier wasn’t biased to be linear, the oscillations couldn’t build up. So I reduced the collector resistor to 6.8k, and changed the the base bias resistor to 1.8M to get the collector voltage into a linear region. So now we have Vc=3.2V with a 5V supply.

Read more.


Join 4,000+ makers on Adafruit’s Discord channels and be part of the community! http://adafru.it/discord

Learn “How Computers Work” with Bill Gates, Ladyada and more – From Code.org !

CircuitPython in 2018 – Python on Microcontrollers is here!

Have an amazing project to share? Join the SHOW-AND-TELL every Wednesday night at 7:30pm ET on Google+ Hangouts.

Join us every Wednesday night at 8pm ET for Ask an Engineer!

Follow Adafruit on Instagram for top secret new products, behinds the scenes and more https://www.instagram.com/adafruit/


Maker Business — Pololu’s New Machines

Wearables — Mystical elements

Electronics — Disable unused channels!

Biohacking — Two Blood Meters to Start Your Biohacking Adventure

Get the only spam-free daily newsletter about wearables, running a "maker business", electronic tips and more! Subscribe at AdafruitDaily.com !



No Comments

No comments yet.

Sorry, the comment form is closed at this time.