RoHS and Germanium.

[newfish]

Hi -

I recently picked up one of the 'Joyo' Voodoo Octave fuzzes.

Cheap, well-made, and with full-size components for modding - can't really go wrong in my book.

I have a question though...

The literature / pedal's label state that the pedal is RoHS compliant, yet there are four Germanium diodes inside.

I thought the likes of OA90 / OA91 etc (which these appear to be!) were being phased out, due to the harmful (Arsenic?) doping process applied to Ge.

Any thoughts on this?

Cheers!

Ian.

[slacker]

RS lists OA90 and other germanium diodes as "RoHS Status Not Applicable" rather than "non compliant" this apparently means someone has decided they don't fall with in the scope of ROHS.

http://uk.rs-online.com/web/p/products/0271527/

EDIT: actually that might be rubbish, it might just be because they don't sell them any more so it's not relevant.

[PRR]

BTW, RoHS does NOT cover Arsenic.

1.Lead (Pb)
2.Mercury (Hg)
3.Cadmium (Cd)
4.Hexavalent chromium (Cr6+)
5.Polybrominated biphenyls (PBB)
6.Polybrominated diphenyl ether (PBDE)

Anyway: The amount of dopant is VERY small. I don't have Ge info but in Si we are talking 1/10^12 or so.

There may be more arsenic in the dust on the diode (it's everywhere) than in the junction.

These materials are not absolutely banned; 1000PPM is allowed.(*)

The main issue in electronics is that we liked to "tin" the leads for easy solderability. "Tin" really being a tin-lead concoction, solder. No more of that!

A second issue is Mercury. Good inside small-signal relays, also hi-current relays, and especially in low-force high-current switching. I am hoarding two good/bad-old Mercury thermostats as back-ups to my silly-state CPU-ed furnace gizmo. (And in my old house, I hunted for a NOS boiler safey switch.)

(*) Cadmium used to be another plating material. Apparently it is very bad. Only 100PPM allowed.

Another looper: Compliance is up to the producer. OA90 and friends have not been produced in decades. Many of their makers are long-gone. The present owners of these brands can not be asked to find and destroy parts made decades ago.

[Kesh]

(*) Cadmium used to be another plating material. Apparently it is very bad. Only 100PPM allowed.

Cadmium is why LDRs/vactrols are problematic. Buy them while you can.