Re: Diode Rectifier Differences (Repost)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Bert Hickman by way of Terry Fritz <teslalist-at-qwest-dot-net>" <bert.hickman-at-aquila-dot-net>

Hi Matt,

"Glass passivation" is a process that adds a protective layer of glass 
above the PN junction (and sometimes the entire silicon die) to prevent 
parameter changes or other degradation of the device under high humidity or 
high temperature conditions. Glass passivated devices are commonly 
specified where either high reliability or reliable operation under harsh 
environmental conditions is needed, such as automotive, aerospace, 
military, and telecommunications.

Using industry standard part designations, the 1N5408 is unpassivated while 
the 1N5408G is the same root device with glass passivation. For indoor 
Tesla Coiling, either type can be used. From a performance standpoint, the 
unpassivated device may be a bit more robust, since most vendors spec it 
with a higher forward surge current rating. However, if your system will be 
housed in area that's not temperature/humidity controlled (such as an 
unheated porch or a pole barn), go with the 1N5408G device.

The 1N5408-T and 1N5408G-T devices you have found are NOT industry standard 
part designations, and I was unable to find ANY spec sheets that covered 
them. While the latter part is _most likely_ glass passivated, it's not 
clear that the 1N5408-T is (regardless of the seller's description). I'd 
recommend using a different vendor and going with industry standard parts 
so that you know exactly what you're buying.

Good luck and best regards,

-- Bert --
-- 
Bert Hickman
Teslamania, from Stoneridge Engineering
"Electromagically" (TM) Shrunken Coins
http://www.teslamania-dot-com


Tesla list wrote:
>Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
><Mddeming-at-aol-dot-com>
>In a message dated 12/27/02 12:56:19 PM Eastern Standard Time, Mddeming 
>writes:
>
>
>>Hi Y'All
>>        Could some knowledgeable person explain the difference/advantage 
>> between these diodes (if any) as applies to rectified TC supply?
>>
>>      1N5408        3A 1000V silicon rectifier  -at- $16.80/100
>>      1N5408-T     3A 1000V silicon and glass passivated rectifier  -at- 
>> $19.24/100
>>      1N5408G-T  3A 1000V glass passivated rectifier -at- $30.30/100
>>
>>Thanks,
>>Matt D.
>
>