EEVblog #236 - FE-5680A Rubidium Standard Teardown

PART 1: http://www.youtube.com/watch?v=I55uLRRvLCU
What's inside the FE-5680A Rubidium frequency standard?
Available on ebay for about $50 or so.

Category:

Science & Technology

Tags:

• rubidium
• frequency
• standard
• fe-5680a
• ebay
• dtcxo
• how
• it
• works
• diy
• serial
• teardown
• stability
• counter
• tutorial
• philips
• input
• output
• oven
• stabilised
• oscillator
• rb
• atomic
• clock
• 10mhz
• sine
• wave
• power
• consumption
• measurement
• 5v
• voltage
• supply
• multimeter
• Electronics
• Technology
• hyperfine
• transition
• atom
• Physics
• package
• dds
• chip
• direct
• digital
• synthesis
• ham
• radio
• crystal
• piezoelectric
• piezoceramic
• ceramic
• vibration

[clodester]

I love your videos but your constant surprised inflection which gets higher and higher makes me for and unknown reason, very anxious and in a strange way, worn out just listening.

But excellent vids, just talk naturally.

[EEVblog]

@clodester I *AM* talking naturally. It's called a High Rising Terminal, google it. Common in Australia. Not everyone speaks like a Yank.

[gglovato]

Dave, shouldn't you update the copyright at the end to (c) 2012 ?

[EEVblog]

@gglovato Yes, but I'm too lazy.

[PirateRadioPoland]

So I think it's time to build an atomic alarm clock!

[EEVblog]

@PirateRadioPoland Begging for it! Some of these have 1pps output too.

[fingerboy18]

Wow, Dave. You're releasing videos like a madman and I love it!

[Mikkel324]

The foam is indeed for thermal insulation. Both the lamp and the resonance cell need to be quite hot to work (to keep the Rb in vapor form). Most of the input power is used to heat these parts, not to drive the lamp. This is why it takes a few minutes to start up and why it draws a higher current during startup.

The "tombstoned" cap is not a bodge. The Rb lamp is RF-excited and this cap is the resonant cap in series with the exciter coil. There's probably a high RF voltage on the free end.

[qwaqwa1960]

*Intentional* tombstoned cap!? Yeah, right.

Piezo? Uh huh... PTC as already mentioned.

The foam is almost certainly thermal insulation.

But, hey, thanx for making the availability of these magnificent beasties known!!! Mine's on its way. Plan to slap on a little touchscreen GUI and a high-freq DDS, and end up with a 1? ppb 0-400MHz generator. Nice.

[UnbrokenCheese]

I picked up one of these about 1-2 years ago, and started to build a nixie clock around it. Kinda lost interest in nixies. All I have to do is finish writing the AVR firmware (NOT Arduino), but it'll likely keep being a dust collector.

[aljaz55]

@zaprodk

I agree. It looks like a PTC, which is bacically a self-regulating heater.

[CampKohler]

Can you find a schematic for it?

[zaprodk]

I think the stuff on top of the xtal is a small PTC pellet for heating it!

[clodester]

@EEVblog I know not everybody speak like and Yank. That would be worse. In ENGLAND, where I live, we also use the term high, or rising infliction.