"David Eather" <eather@tpg.com.au> wrote in news:op.xt37nkhawei6gd@phenom-
pc.asus:
> On Mon, 16 Feb 2015 04:36:51 +1000, Michael Black <et472@ncf.ca> wrote:
>
>> On Sun, 15 Feb 2015, David Eather wrote:
>>
>>> On Sat, 14 Feb 2015 11:49:36 +1000, Michael Black <et472@ncf.ca> wrote:
>>>
>>>> On Fri, 13 Feb 2015, M. Hamed wrote:
>>>>
>>>>> On Thursday, February 12, 2015 at 11:19:36 PM UTC-7, Phil Allison
>>>>> wrote:
>>>>>> ** Well, they are cleary zener diodes - like the link says.
>>>>>>
>>>>> Have you ever seen low forward voltage zener diodes? That would be
>>>>> new to me. The forward drop on these are about .2V-.3V
>>>>>
>>>> A zener by definition is reverse biased.
>>>
>>> Not so, and by the way all diodes are zener diodes - we just don't
>>> normally run them in the breakdown region.
>>
>> Yes, all diodes can "zener" but they are reversed biased.
>
>
> So what?
So shut up and humble yourself, asshole.
Reply by George Herold●February 21, 20152015-02-21
On Saturday, February 21, 2015 at 8:12:00 AM UTC-5, Baron wrote:
> George Herold prodded the keyboard with:
>
> > For best results as a detector get the 113R "clear"
> > sand down most of the plastic till you get near the wire bond
> > and then polish out the scratches.
> >
> > George H.
>
> Hi George,
> You can flame polish the plastic. Just touch the plastic into a small
> flame until it starts to melt, it only takes a couple of seconds or
> so. I use this method on the lathe to polish the lens ends on 1/2"
> perspex rod.
> --
> Best Regards:
> Baron.
Oh thanks I hadn't thought of that.
(I use a bit of spit as a temporary solution.)
George H.
Reply by Baron●February 21, 20152015-02-21
George Herold prodded the keyboard with:
> For best results as a detector get the 113R "clear"
> sand down most of the plastic till you get near the wire bond
> and then polish out the scratches.
>
> George H.
Hi George,
You can flame polish the plastic. Just touch the plastic into a small
flame until it starts to melt, it only takes a couple of seconds or
so. I use this method on the lathe to polish the lens ends on 1/2"
perspex rod.
--
Best Regards:
Baron.
Reply by George Herold●February 20, 20152015-02-20
On Thursday, February 19, 2015 at 9:59:54 PM UTC-5, Maynard A. Philbrook Jr. wrote:
> In article <57752ec8-c635-4488-9a4b-4a37116e33fc@googlegroups.com>,
> gherold@teachspin.com says...
> >
> > On Thursday, February 19, 2015 at 7:08:23 PM UTC-5, Maynard A. Philbrook Jr. wrote:
> > > In article <e7586579-3c71-4500-a14d-7f52852f941b@googlegroups.com>,
> > > gherold@teachspin.com says...
> > > > > >>
> > > > > >> Yes, all diodes can "zener" but they are reversed biased.
> > > > > >
> > > > > >A word of warning: don't test the reverse bias on point-contact,
> > > > > >or light emitting, or low-noise photodiodes.
> > > > >
> > > > > Reverse biasing photodiodes is the usual way to use them. It reduces
> > > > > their capacitance and makes them a lot faster.
> > > >
> > > > Anyone tried taking a garden variety photodiode up to the point
> > > > where it starts avalanching?
> > > > (Maybe in a dark room... there are some thing better done with the
> > > > lights off :^)
> > > >
> > > > George H.
> > > >
> > > >
> > >
> > > did that with a clear LED using a 1M R as a ballast .
> > >
> > > It gave some interesting results at around 25V
> > >
> > >
> > > Jamie
> >
> > Me too! (it all started on SEB after all.)
> > http://teachspin.com/newsletters/TeachSpin_MAY13FINALFOR%20WEB.pdf
> >
> > The leds are from purdy electronics AND113R and AND114R
> > http://www.purdyelectronics.com/products/red_leds
> >
> > For best results as a detector get the 113R "clear"
> > sand down most of the plastic till you get near the wire bond
> > and then polish out the scratches.
> >
> > George H.
>
> do you also use a file on carbon composite resistors to get
> the value you need when in a pinch, too? ;)
>
> Jamie
I've heard about filling carbon composites, but I've never done it.
(almost all 1% metal film.. though a few CC used for the non-magnetic properties)
George H.
Reply by Jasen Betts●February 20, 20152015-02-20
On 2015-02-19, Pimpom <Pimpom@invalid.invalid> wrote:
> Jasen Betts wrote:
>> On 2015-02-18, George Herold <gherold@teachspin.com> wrote:
>>
>>>> I've seen LEDs in cheap Chinese and Indian products run
>>>> directly
>>>> from 230VAC with a single series resistor and nothing else.
>>>> That
>>>> obviously places the LED in reverse breakdown every half
>>>> cycle. I
>>>> haven't paid enough attention to see if/how their performance
>>>> changes with time.
>>>
>>> I reversed biased several LEDs.. most were good up to ~100V or
>>> so..
>>> 230VAC seems like a lot... but maybe with the "right" led.
>>
>> I killed one with only 9V
>
> Must have been without a series resistor or other current
> limiter.
560R
--
umop apisdn
Reply by Charlie+●February 20, 20152015-02-20
On Thu, 19 Feb 2015 08:02:35 +0000, Charlie+ <charlie@xxx.net> wrote as
underneath :
snip
>>
>I have used since 2002 a couple of 3mm hibright red LEDs like this as
>indicators but running them at less than 0.00005A (240v mains R series
>at 470K) nothing like your figures 1-2mA. So this works fine just for
>indicators but I would be wary of doing this at anything like full LED
>brightness. Output looks same as when installed.
Sorry correction on checking circuit - used these LEDs like this since
1995 when I updated my C/H system... strewth - nearly 20 years ago!
Reply by Maynard A. Philbrook Jr.●February 19, 20152015-02-19
In article <57752ec8-c635-4488-9a4b-4a37116e33fc@googlegroups.com>,
gherold@teachspin.com says...
>
> On Thursday, February 19, 2015 at 7:08:23 PM UTC-5, Maynard A. Philbrook Jr. wrote:
> > In article <e7586579-3c71-4500-a14d-7f52852f941b@googlegroups.com>,
> > gherold@teachspin.com says...
> > > > >>
> > > > >> Yes, all diodes can "zener" but they are reversed biased.
> > > > >
> > > > >A word of warning: don't test the reverse bias on point-contact,
> > > > >or light emitting, or low-noise photodiodes.
> > > >
> > > > Reverse biasing photodiodes is the usual way to use them. It reduces
> > > > their capacitance and makes them a lot faster.
> > >
> > > Anyone tried taking a garden variety photodiode up to the point
> > > where it starts avalanching?
> > > (Maybe in a dark room... there are some thing better done with the
> > > lights off :^)
> > >
> > > George H.
> > >
> > >
> >
> > did that with a clear LED using a 1M R as a ballast .
> >
> > It gave some interesting results at around 25V
> >
> >
> > Jamie
>
> Me too! (it all started on SEB after all.)
> http://teachspin.com/newsletters/TeachSpin_MAY13FINALFOR%20WEB.pdf
>
> The leds are from purdy electronics AND113R and AND114R
> http://www.purdyelectronics.com/products/red_leds
>
> For best results as a detector get the 113R "clear"
> sand down most of the plastic till you get near the wire bond
> and then polish out the scratches.
>
> George H.
do you also use a file on carbon composite resistors to get
the value you need when in a pinch, too? ;)
Jamie
Reply by George Herold●February 19, 20152015-02-19
On Thursday, February 19, 2015 at 7:08:23 PM UTC-5, Maynard A. Philbrook Jr. wrote:
> In article <e7586579-3c71-4500-a14d-7f52852f941b@googlegroups.com>,
> gherold@teachspin.com says...
> > > >>
> > > >> Yes, all diodes can "zener" but they are reversed biased.
> > > >
> > > >A word of warning: don't test the reverse bias on point-contact,
> > > >or light emitting, or low-noise photodiodes.
> > >
> > > Reverse biasing photodiodes is the usual way to use them. It reduces
> > > their capacitance and makes them a lot faster.
> >
> > Anyone tried taking a garden variety photodiode up to the point
> > where it starts avalanching?
> > (Maybe in a dark room... there are some thing better done with the
> > lights off :^)
> >
> > George H.
> >
> >
>
> did that with a clear LED using a 1M R as a ballast .
>
> It gave some interesting results at around 25V
>
>
> Jamie
Reply by Maynard A. Philbrook Jr.●February 19, 20152015-02-19
In article <e7586579-3c71-4500-a14d-7f52852f941b@googlegroups.com>,
gherold@teachspin.com says...
> > >>
> > >> Yes, all diodes can "zener" but they are reversed biased.
> > >
> > >A word of warning: don't test the reverse bias on point-contact,
> > >or light emitting, or low-noise photodiodes.
> >
> > Reverse biasing photodiodes is the usual way to use them. It reduces
> > their capacitance and makes them a lot faster.
>
> Anyone tried taking a garden variety photodiode up to the point
> where it starts avalanching?
> (Maybe in a dark room... there are some thing better done with the
> lights off :^)
>
> George H.
>
>
did that with a clear LED using a 1M R as a ballast .
It gave some interesting results at around 25V
Jamie
Reply by Pimpom●February 19, 20152015-02-19
Jasen Betts wrote:
> On 2015-02-18, George Herold <gherold@teachspin.com> wrote:
>
>>> I've seen LEDs in cheap Chinese and Indian products run
>>> directly
>>> from 230VAC with a single series resistor and nothing else.
>>> That
>>> obviously places the LED in reverse breakdown every half
>>> cycle. I
>>> haven't paid enough attention to see if/how their performance
>>> changes with time.
>>
>> I reversed biased several LEDs.. most were good up to ~100V or
>> so..
>> 230VAC seems like a lot... but maybe with the "right" led.
>
> I killed one with only 9V
Must have been without a series resistor or other current
limiter.