On Wed, 06 Sep 2017 20:15:27 -0700, John Larkin
<jjlarkin@highlandtechnology.com> wrote:
>On Wed, 06 Sep 2017 20:57:44 -0400, krw@notreal.com wrote:
>
>>On Wed, 06 Sep 2017 08:54:57 -0700, John Larkin
>><jjlarkin@highlandtechnology.com> wrote:
>>
>>>On Wed, 6 Sep 2017 07:53:16 -0700 (PDT), dagmargoodboat@yahoo.com
>>>wrote:
>>>
>>>>On Thursday, October 8, 2015 at 3:18:56 AM UTC-4, John Devereux wrote:
>>>>> John Larkin <jjlarkin@highlandtechnology.com> writes:
>>>>
>>>>> > A phototransistor optocoupler will generate a little voltage on the
>>>>> > output side, not enough to be useful for anything I can imagine.
>>>>>
>>>>> Maybe the trick of generating a negative bias current to pull an opamp
>>>>> output down though ground?
>>>>
>>>>
>>>>BTT for the Bob Pease e-b zener negative bias generator discussion
>>>>(for Gerhard, over in the Two-transistor circuits thread)
>>>>
>>>>Nice measurements by piglet and George Herold.
>>>>
>>>>Cheers,
>>>>James Arthur
>>>
>>>There are photovoltaic optocouplers that produce small but useful
>>>amounts of output power, hundreds of microwatts, ballpark 10 volts and
>>>20 uA. Most small SSRs use them internally. I've used them as linear
>>>gate drivers in high-voltage amps.
>>>
>>>https://www.dropbox.com/s/pitngkdfyxa74sh/BIP_HV_REG_4.asc?dl=0
>>>
>>>https://www.dropbox.com/s/qcmlv976j3pm0xi/HV_Reg_4.jpg?raw=1
>>
>>ADI has magnetic couplers that transfer useful power, too. Ain't
>>cheap, though.
>
>I use a lot of those small dual-winding inductors (DRQxxx types) as
>switcher power transformers.
>
>The ADI things are practically broadcast transmitters.
I didn't have any trouble getting one past the FCC.
Reply by John Larkin●September 7, 20172017-09-07
On Wed, 06 Sep 2017 20:57:44 -0400, krw@notreal.com wrote:
>On Wed, 06 Sep 2017 08:54:57 -0700, John Larkin
><jjlarkin@highlandtechnology.com> wrote:
>
>>On Wed, 6 Sep 2017 07:53:16 -0700 (PDT), dagmargoodboat@yahoo.com
>>wrote:
>>
>>>On Thursday, October 8, 2015 at 3:18:56 AM UTC-4, John Devereux wrote:
>>>> John Larkin <jjlarkin@highlandtechnology.com> writes:
>>>
>>>> > A phototransistor optocoupler will generate a little voltage on the
>>>> > output side, not enough to be useful for anything I can imagine.
>>>>
>>>> Maybe the trick of generating a negative bias current to pull an opamp
>>>> output down though ground?
>>>
>>>
>>>BTT for the Bob Pease e-b zener negative bias generator discussion
>>>(for Gerhard, over in the Two-transistor circuits thread)
>>>
>>>Nice measurements by piglet and George Herold.
>>>
>>>Cheers,
>>>James Arthur
>>
>>There are photovoltaic optocouplers that produce small but useful
>>amounts of output power, hundreds of microwatts, ballpark 10 volts and
>>20 uA. Most small SSRs use them internally. I've used them as linear
>>gate drivers in high-voltage amps.
>>
>>https://www.dropbox.com/s/pitngkdfyxa74sh/BIP_HV_REG_4.asc?dl=0
>>
>>https://www.dropbox.com/s/qcmlv976j3pm0xi/HV_Reg_4.jpg?raw=1
>
>ADI has magnetic couplers that transfer useful power, too. Ain't
>cheap, though.
I use a lot of those small dual-winding inductors (DRQxxx types) as
switcher power transformers.
The ADI things are practically broadcast transmitters.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
Reply by ●September 6, 20172017-09-06
On Wed, 06 Sep 2017 08:54:57 -0700, John Larkin
<jjlarkin@highlandtechnology.com> wrote:
>On Wed, 6 Sep 2017 07:53:16 -0700 (PDT), dagmargoodboat@yahoo.com
>wrote:
>
>>On Thursday, October 8, 2015 at 3:18:56 AM UTC-4, John Devereux wrote:
>>> John Larkin <jjlarkin@highlandtechnology.com> writes:
>>
>>> > A phototransistor optocoupler will generate a little voltage on the
>>> > output side, not enough to be useful for anything I can imagine.
>>>
>>> Maybe the trick of generating a negative bias current to pull an opamp
>>> output down though ground?
>>
>>
>>BTT for the Bob Pease e-b zener negative bias generator discussion
>>(for Gerhard, over in the Two-transistor circuits thread)
>>
>>Nice measurements by piglet and George Herold.
>>
>>Cheers,
>>James Arthur
>
>There are photovoltaic optocouplers that produce small but useful
>amounts of output power, hundreds of microwatts, ballpark 10 volts and
>20 uA. Most small SSRs use them internally. I've used them as linear
>gate drivers in high-voltage amps.
>
>https://www.dropbox.com/s/pitngkdfyxa74sh/BIP_HV_REG_4.asc?dl=0
>
>https://www.dropbox.com/s/qcmlv976j3pm0xi/HV_Reg_4.jpg?raw=1
ADI has magnetic couplers that transfer useful power, too. Ain't
cheap, though.
Reply by George Herold●September 6, 20172017-09-06
On Wednesday, September 6, 2017 at 11:55:12 AM UTC-4, John Larkin wrote:
> On Wed, 6 Sep 2017 07:53:16 -0700 (PDT), dagmargoodboat@yahoo.com
> wrote:
>
> >On Thursday, October 8, 2015 at 3:18:56 AM UTC-4, John Devereux wrote:
> >> John Larkin <jjlarkin@highlandtechnology.com> writes:
> >
> >> > A phototransistor optocoupler will generate a little voltage on the
> >> > output side, not enough to be useful for anything I can imagine.
> >>
> >> Maybe the trick of generating a negative bias current to pull an opamp
> >> output down though ground?
> >
> >
> >BTT for the Bob Pease e-b zener negative bias generator discussion
> >(for Gerhard, over in the Two-transistor circuits thread)
> >
> >Nice measurements by piglet and George Herold.
> >
> >Cheers,
> >James Arthur
>
> There are photovoltaic optocouplers that produce small but useful
> amounts of output power, hundreds of microwatts, ballpark 10 volts and
> 20 uA. Most small SSRs use them internally. I've used them as linear
> gate drivers in high-voltage amps.
>
> https://www.dropbox.com/s/pitngkdfyxa74sh/BIP_HV_REG_4.asc?dl=0
>
> https://www.dropbox.com/s/qcmlv976j3pm0xi/HV_Reg_4.jpg?raw=1
>
>
> --
>
> John Larkin Highland Technology, Inc
>
> lunatic fringe electronics
Sometime in the past I tried stacking up a bunch of the PV opto-couplers
to make a 5V- 100V DC source. The output impedance was the pits.
George H.
Reply by John Larkin●September 6, 20172017-09-06
On Wed, 6 Sep 2017 07:53:16 -0700 (PDT), dagmargoodboat@yahoo.com
wrote:
>On Thursday, October 8, 2015 at 3:18:56 AM UTC-4, John Devereux wrote:
>> John Larkin <jjlarkin@highlandtechnology.com> writes:
>
>> > A phototransistor optocoupler will generate a little voltage on the
>> > output side, not enough to be useful for anything I can imagine.
>>
>> Maybe the trick of generating a negative bias current to pull an opamp
>> output down though ground?
>
>
>BTT for the Bob Pease e-b zener negative bias generator discussion
>(for Gerhard, over in the Two-transistor circuits thread)
>
>Nice measurements by piglet and George Herold.
>
>Cheers,
>James Arthur
On Thursday, October 8, 2015 at 3:18:56 AM UTC-4, John Devereux wrote:
> John Larkin <jjlarkin@highlandtechnology.com> writes:
> > A phototransistor optocoupler will generate a little voltage on the
> > output side, not enough to be useful for anything I can imagine.
>
> Maybe the trick of generating a negative bias current to pull an opamp
> output down though ground?
BTT for the Bob Pease e-b zener negative bias generator discussion
(for Gerhard, over in the Two-transistor circuits thread)
Nice measurements by piglet and George Herold.
Cheers,
James Arthur
Reply by piglet●October 18, 20152015-10-18
On 17/10/2015 03:03, George Herold wrote:
>
> I have a final piece of temperature data,
> I don't have freeze spray, but I hit the
> transistor with a heat gun (on low) and warmed it
> up till Icb decreased by ~10%, At the same time the
> 2 mA of eb current (monitored with 1 k ohm,
> driven from a voltage source) decreased by ~5%.
> (The numbers are a bit loose, holding a heat gun,
> looking at meters and writing down numbers.)
>
> The measurements were disappointing in that
> the Icb (@constant Ibe) decreased by ~10% during the
> ~1/2 hour I was taking data. Zenering eb at 1-2 mA
> is not so good. (at least for 2N3904's)
>
> piglet, I think I'm done playing with this.
> I'm not sure of the mechanism, I'd lean
> more towards the photo idea, mostly because
> of the temperature data, but I wouldn't be
> surprised if Phil was right.
>
>
> "When you wake up in the morning, Pooh," said Piglet at last, "what's the first thing you say to yourself?"
>
> "What's for breakfast?" said Pooh. "What do you say, Piglet?"
>
> "I say, I wonder what's going to happen exciting today?" said Piglet.
>
> Pooh nodded thoughtfully. "It's the same thing," he said."
> -- A.A. Milne
>
> We'll find some exciting thing tomorrow. :^)
> George H.
>
Gosh, George it is exciting to read another post of yours! That is very
good work. C-B does look to me like a photodiode.
It does look (pun accidental) as if the photoelectric idea is at play
here. I can see (pun intended) light coming from an avalanched E-B jct
and I can see (pun intended) the C-B jct is photo-sensitive to external
room light so placing the two next to each other looks (wow-another pun)
kinda obvious. However I am also happy to accept diffision could also be
happening, solid-state physics is pretty much a closed book to me.
piglet
Reply by George Herold●October 16, 20152015-10-16
On Friday, October 16, 2015 at 4:39:04 PM UTC-4, George Herold wrote:
> On Friday, October 16, 2015 at 9:27:23 AM UTC-4, George Herold wrote:
> > On Friday, October 16, 2015 at 8:48:30 AM UTC-4, piglet wrote:
> > > On 16/10/2015 03:51, George Herold wrote:
> > > > Hey for the photon idea,
> > > > Take off the "top" and see how much light there
> > > > is when you zener cb.
> > > > (Well that only checks my no photons get through idea.)
> > > >
> > > > Can you grind a to-92, dissolve the plastic?
> > > >
> > >
> > > Here are two photos:
> > >
> > > <https://www.dropbox.com/s/6rkc80amj2aybuk/Veb_Setup.jpg>
> > > My setup of an old TO-18 npn with lid snipped open.
> > >
> > > <https://www.dropbox.com/s/2fvi5i6tsphp0yg/Veb_AvalancheLEQ.jpg>
> > > Shows a spot of light from the die when E-B broken down. Note the camera
> > > gets the colour badly wrong - the image redish/orange is really
> > > blueish-white just as Jeroen described. I had to use 20mA to get it
> > > bright enough to photograph and then I still had to enhance the image.
> > >
> > > I tried breaking down the C-B junction but saw no light, but lack of
> > > high enough voltage meant avalanche current was 400-500uA (which when
> > > E-B breaks down does make enough light for the eye to see).
> > >
> > > However I can confirm that the E-B junction is photo-sensitive to room
> > > lighting like the C-B junction. So if C-B avalanche were to emit photons
> > > then I think the E-B junction ought to respond. My guess is therefore
> > > that only E-B breakdown makes light.
> > >
> > > piglet
> >
> > Hi piglet, I thought I might try this today.
> > https://www.dropbox.com/s/ja9ce4cgvtt8zz3/Icb_vs_Vcb.JPG?dl=0
> >
> > Measure the current as a function of Vcb, which I think was one of
> > Phil's ideas... though I'm not sure. Hopefully
> > he'll respond. In theory this should show no change in the current
> > if it's a photo thing. (Well at very small voltages maybe a small increase.)
> > And I think the diffusion idea would show more current with higher
> > ~10's of volts on Vcb. How much more I'm not sure.
> >
> > Anyway I'm going to buckle down, get my work done and may have some time in the afternoon.
> >
> > Later,
> > George H.
>
> Finished work at ~3:00 and by 3:40 my lab bench looked like this,
> https://www.dropbox.com/s/d8y8hpwyy5jbzw0/DSCN0181.JPG?dl=0
>
> So I've got a nice TIA to measure the base-collector current.
> First results for zero bias on Vbc.
>
> Ibe(mA) Ibc(nA)
> 0.303 32
> 0.605 64
> 1.02 108
> 2.003 210
> 4.01 407
> 8.01 760
>
> The 3904 is linear now too...
>
> I then tried to take data at a fixed Ibe and change Vcb. But it
> didn't work so well, the emitter base current would drift around.
> (probably not the most stable power supplies.)
> So then I looked at changes in Icb as I switched Vcb from 0 to 50 V.
> In which case I say about a 1% increase in the Icb
>
> Ibe(mA) Icb(Vcb=0) Icb(Vcb=50V)
> 1.003 99.6 100.7
> 2.003 198.1 199.8
> 4.01 387.7 391.1
>
> Phil is this the magnitude of the expected change for your
> diffusion idea?
>
> As some final data I was trying to see if the change is linear in Vbc.
> The problem is things are not at all stable at the 1% level. I set
> Ibe for 2.0 mA measured Icb, increased Vcb to some voltage, record number,
> reduce back to zero, record number.
>
> So the nominal current was ~190nA,
> the change at
> 50 V was 1.85 nA
> 25 V was 1.2 nA
> 11 V was 0.9 nA
>
> For whatever it's worth it doesn't look to be linear.
> (maybe squarerootish)
>
> George H.
I have a final piece of temperature data,
I don't have freeze spray, but I hit the
transistor with a heat gun (on low) and warmed it
up till Icb decreased by ~10%, At the same time the
2 mA of eb current (monitored with 1 k ohm,
driven from a voltage source) decreased by ~5%.
(The numbers are a bit loose, holding a heat gun,
looking at meters and writing down numbers.)
The measurements were disappointing in that
the Icb (@constant Ibe) decreased by ~10% during the
~1/2 hour I was taking data. Zenering eb at 1-2 mA
is not so good. (at least for 2N3904's)
piglet, I think I'm done playing with this.
I'm not sure of the mechanism, I'd lean
more towards the photo idea, mostly because
of the temperature data, but I wouldn't be
surprised if Phil was right.
"When you wake up in the morning, Pooh," said Piglet at last, "what's the first thing you say to yourself?"
"What's for breakfast?" said Pooh. "What do you say, Piglet?"
"I say, I wonder what's going to happen exciting today?" said Piglet.
Pooh nodded thoughtfully. "It's the same thing," he said."
-- A.A. Milne
We'll find some exciting thing tomorrow. :^)
George H.
Reply by George Herold●October 16, 20152015-10-16
On Friday, October 16, 2015 at 5:50:54 PM UTC-4, whit3rd wrote:
> On Tuesday, October 13, 2015 at 5:45:58 PM UTC-7, George Herold wrote:
> > On Tuesday, October 13, 2015 at 7:21:19 PM UTC-4, whit3rd wrote:
>
> > > There's a built-in field in a junction (as long as you're away from zero temperature)
> > > because of diffusion of high-density (majority) carriers in both the N and P regions.
> [and charged particles are accelerate and and generate energy}
> > > I don't suppose any SPICE models really capture this effect, do they?
>
> > OK can you explain why we see nothing when we zener the BC jucntion
> > at ~100V and 1-2 mA? The steeper BE junction should
> > pull in more of the base carriers. No?
> > (This is fun! :^)
>
> It might be geometry; the CB breakdown generates carriers over the full area
> of the base, but you only harvest current in the smaller area of the BE depletion
> region. Any charge that recombines before it gets to the depletion zone
> doesn't get any acceleration, and no net energy is generated.
> It might be amusing to experiment on CMPT404A or other chopper transistor with
> symmetric beta (which implies some geometry symmetry).
>
> Another issue is the thinner BE depletion region, due to higher doping.
> That charge cloud has to separate while traversing the depletion region,
> or no net generation occurs. If it spends little time in the region, the
> separation (0.5 * a *t**2) is small regardless of the high field intensity, the "a" factor.
Hmm OK, My understanding of the diffusion idea,
is that all it takes is charge in the base,
then some diffuse into the other junction.
I was thinking that the same base current
should cause similar amounts of diffusion current.
George H.
Reply by whit3rd●October 16, 20152015-10-16
On Tuesday, October 13, 2015 at 5:45:58 PM UTC-7, George Herold wrote:
> On Tuesday, October 13, 2015 at 7:21:19 PM UTC-4, whit3rd wrote:
> > There's a built-in field in a junction (as long as you're away from zero temperature)
> > because of diffusion of high-density (majority) carriers in both the N and P regions.
[and charged particles are accelerate and and generate energy}
> > I don't suppose any SPICE models really capture this effect, do they?
> OK can you explain why we see nothing when we zener the BC jucntion
> at ~100V and 1-2 mA? The steeper BE junction should
> pull in more of the base carriers. No?
> (This is fun! :^)
It might be geometry; the CB breakdown generates carriers over the full area
of the base, but you only harvest current in the smaller area of the BE depletion
region. Any charge that recombines before it gets to the depletion zone
doesn't get any acceleration, and no net energy is generated.
It might be amusing to experiment on CMPT404A or other chopper transistor with
symmetric beta (which implies some geometry symmetry).
Another issue is the thinner BE depletion region, due to higher doping.
That charge cloud has to separate while traversing the depletion region,
or no net generation occurs. If it spends little time in the region, the
separation (0.5 * a *t**2) is small regardless of the high field intensity, the "a" factor.