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First the Basics, Then the Complicated Stuff

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zeeglen
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Re: Things we ought to know
zeeglen   6/16/2014 7:28:55 PM
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@Max  Don't keep us in suspense ... why? LOL

I suspect it was because when one looks at a SOT143 package one automatically thinks "transistor", the extra pin for lower inductance at a BJT emitter or connection to the substrate of a FET.

JCreasey
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Re: Observe that no current will ever flow. We all can see that, right?
JCreasey   6/16/2014 6:12:59 PM
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@Max....Of course in reverse avalanche the LED may well output photons (mainly Blue light and the magic smoke that accompanies it)....but you have to really want it!

Max The Magnificent
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Re: Observe that no current will ever flow. We all can see that, right?
Max The Magnificent   6/16/2014 4:35:27 PM
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@JCreasey: ...and of course you won't get any black light out of it....now that was a giggle...

What? That wasn't true? :-)

David Ashton
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Re: Things we ought to know
David Ashton   6/16/2014 4:31:19 PM
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@Max....Flattery will get you everywhere.  That's worth at least one beer at EELive 2015.  

PS: That must be why everyone keeps saying "Don't let David get his hands on it...."

JCreasey
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Observe that no current will ever flow. We all can see that, right?
JCreasey   6/16/2014 2:44:55 PM
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It's funny to see someone make simple assumptions that are probably wrong.

With the simple circuit and two "diodes" in series opposition one might conclude that only leakage current would flow for either polarity of input. But simple dismissal of the circuit may not be quite right.

Most LED's have extremely low reverse voltage capability. Most around 5-6V, or if they are more advanced, they have a parallel bulk protection diode in place and have a reverse voltage rating of only .8-1.2V.

In either case and with this circuit it's highly likely that current will flow for the AC half cycle shown.

In the case of Vr breakdown it might be 6V or so....add the protection diode Vf and you'd see something of the order of 7V across the diodes and about 9V across the resistor (about 17v peak from the AC 12v input). Current will flow (9/R) and it's unlikley to damage the LED (and of course you won't get any black light out of it....now that was a giggle)

There is no doubt that the circuit is non-ideal, but explaining that you must consider both polarities of input and the characteristics of the LED might have been better than dismissal.

Max The Magnificent
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Re: First post!
Max The Magnificent   6/16/2014 1:15:39 PM
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@AndrewAPTemple: And, I look forward to more interaction with the community (as opposed to only reading the articles), and the jokes!

I lot of us have formed lasting friendships via EETimes and its sister sites -- some of us even manage to meet up at conferences. Maybe you will be able to attend some of these conferences after you've finished being a student. Where abouts are you based?

AndrewAPTemple
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Re: First post!
AndrewAPTemple   6/16/2014 1:01:30 PM
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You cannot help but forget things -- especially things you don't use on a daily basis -- one of the best ways to stay on top of things (I think) is to have hobby projects that are outside of your usual work activities, because when you have a task to do you have to learn how to do it, and as long as you are learning stuff you seem to be better able to remember other stuff. 

I'll keep those words in mind, especially when I finally I got into this professional, managerial world I keep hearing about. 

And, I look forward to more interaction with the community (as opposed to only reading the articles), and the jokes!

Max The Magnificent
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Re: First post!
Max The Magnificent   6/16/2014 12:48:41 PM
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@antedeluvian: I find it quite disheartening when I put several hours into a blog and it seems to fall on deaf ears.

I knwo just what you mean -- sometimes I slog away at a column ... and no one says anything ... I'd like to think it was because they were left speechless by my brilliance, but I fear thsi is not the case LOL

On the other hand, when I post a blog like my recent Thanks, Dad! that gets a bunch of comments, then I bounce aroudn with a great big sloppy grin on my face :-)

Max The Magnificent
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Re: First post!
Max The Magnificent   6/16/2014 12:45:14 PM
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@AndrewAPTemple: I first off want to say hello to the community of EE Times! Even after being a member of the site for a while now, this is first time I have ever decided to leave a comment!

Hello there -- welcome aboard :-) Hopefully we'll be seeing a lot more of you (comment-wise).

I make a lot of jokes about management and managers, but they do provide a necessary function (being the butt of my jokes, for example :-)

You cannot help but forget things -- especially things you don't use on a daily basis -- one of the best ways to stay on top of things (I think) is to have hobby projects that are outside of your usual work activities, because when you have a task to do you have to learn how to do it, and as long as you are learning stuff you seem to be better able to remember other stuff.

Max The Magnificent
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Re: "That's the only way it would compile"
Max The Magnificent   6/16/2014 12:40:35 PM
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@Betajet: When he pointed this out, the hapless student said: "But that's the only way I could get it to compile!"

Rolling on the floor laughing out loud!!!

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