Advertisements

Archive for September 20th, 2017

60 kHz Tuning Fork Resonator: Maximum Overdrive

Datasheets loosely associated with the tuning fork resonators in hand suggest 1 μW maximum drive power, which works out to maybe 100 mVrms = 150 mVpk at about 10 kΩ ESR. If you inadvertently apply 500 mVpk = 375 mVrms, the resulting 14 μW does this:

Broken 60 kHz Tuning Fork Resonator - overview

Broken 60 kHz Tuning Fork Resonator – overview

I was applying a precisely tuned 60 kHz sine wave to the first pass at a crystal filter grafted onto the loop antenna preamp and wasn’t paying attention to the amplitude. For all I know, though, the poor thing died from a power-on transient. I’m pretty sure I didn’t break it during extraction, because it stopped being a resonator while in the circuit.

The missing tine fell out of the can:

Broken 60 kHz Tuning Fork Resonator - tine detail

Broken 60 kHz Tuning Fork Resonator – tine detail

Laser trim scars form a triangle near the tip, a T a bit further down, a slot just above the nicely etched gap.

A closer look at the fractured base:

Broken 60 kHz Tuning Fork Resonator - detail

Broken 60 kHz Tuning Fork Resonator – detail

The metalization appears black here and gold in person.

So, yeah, one down and 49 to go …

Advertisements

,

2 Comments