Different Semiconductor Devices

[ele1200]

I am looking for information of the following. Maybe you guys know where to find info as my text books do not have that much info. Thanks<p>SCR-Shockley Diode-Triac<p>Most Obscure (are these used much??)<p>Diac-SBS-UJT-PUT-SCS-GTO-LASCR-MOV<p>What do these do???? Help Me<p>[ November 14, 2002: Message edited by: newguy ]</p>

[billdar]

This is like a nice little trivia quiz...<p>I know for sure the SCR is a silicon controlled
rectifyer. Only used one once. Its a three-
lead device, looks like a diode with an extra
wire off the cathode for schematic work. Funtions
like a diode with an on/off switch.<p>Im sure someone else can give a better explanation.<p>ps. Is shockley a typo? I've heard of schotkey
diodes, they are used to protect the silicon core
of an IC from a static discharge at the pins...

[bodgy]

well Shockley was one of the co-conspirators in the Bell labs transistor debut - Brain and I forget the other person - my dynamic memory banks need faster refreshing these days.<p>
bodgy

[Len]

Just about all of your devices are described in "Electronic Components Hobby Manual" published by GE in 1965. You might try to find a copy at a flea market or Hamfest. Here are a few
UJT- (unijunction transistor) a useful pulse generator before the 555 came along but still useful to trigger SCRs.
PUT- (programable UJT) a special form of UJT
DIAC- (diode,a-c) special diodes with specific breakdown voltages; used to trigger Triacs.
LASCR (light activated SCR) a special form of SCR that can be triggered by light.
MOV (metal oxide varistor) a common component used in surge protectors; come in various breakdown voltages that clamp voltage spikes when the threshold is reached.

[russlk]

The Shockley diode is a four layer device used as a trigger or switching diode. I believe it is now called SBS, silicon bilateral switch. I don't know what the difference is between these and a DIAC, if any.

[Edd]

Bill:
Looks like all were well covered by others except posssibly the NON-Pontiac....GTO...Gate turn off thyristor.
Big ole hi power puppies except maybe the lo
pwr units that that Sony used in some deflection ckts back in the '70's;check out :
http://www.parcon.uci.edu/paper/eepower.htm
On the old (William) Shockley diode I send this just to refresh my memory bank on its schematic
symbolization. As well, a couple of other units are on the same page:
http://www.pbs.org/transistor/science/info/4ldiode.html
Also:
http://www.americanmicrosemi.com/tutorials/diac.htm <p>73’s de Edd
[email protected] (Interstellar~~~~Warp~~~~Speed)
[email protected] (Firewalled-Spam*Cookies*Crumbs)<p>

[greg123]

Sombody correct me on this if i am wrong.....(Dean you there? i think you have an article on diacs in poptronics this month)<p>A diac can conduct in both directions to trigger while a shockly diode can only conduct in only one direction.

[Dean Huster]

As a matter of fact, you are correct about the article, Greg. In the December 2002 issue of Poptronics in the "Q & A" column, a reader brought up the subject of a diac (bidirectional trigger diode). A diac is essentially the solid-state equivalent of a neon lamp in characteristics, albiet working at lower voltages. The December issue is on your newstands as I write this. Along with Nuts & volts, it's an excellent hobbyist magazine that is well worth the money, especially if you subscribe rather than buying it by the issue (for the cost of three issues from Barnes and Noble, you can purchase an entire year's subscription).<p>By the way, don't confuse a Shockley diode with a Schottky diode. A Schottky diode, aka a hot-carrier diode, has a very low forward drop of maybe 0.1v at full current but is pretty leaky in the reverse direction. They're used in LS TTL chips (that's the "S" in TTL chips) and as rectifiers in low-voltage, high-efficiency power supplies because they don't waste a lot of power.<p>And that's Shockley, Brittain and Bardeen at Bell Labs who are credited with the transistor's invention.<p>Dean<p>[ November 16, 2002: Message edited by: Dean Huster ]</p>

[Joseph]

I have been a subscriber for almost 15 years. Dean, I am partial to your column, you know.<p>The voltage drop across a Schottky can range from about .1 volt at low current to about .7 at max current. They have roughly half the forward voltage drop of a standard rectifier diode, can switch fast, but don't block very much reverse voltage.<p>PBS aired a documentary about Shockley, Brittain and Bardeen. I not sure if it was on Nova or maybe Frontline.<p>[ November 17, 2002: Message edited by: Joseph Meisenhelder ]</p>

[ele1200]

What about the SBS and the SCS......Dean??