BJT behaviour at ridiculously low current levels...

[John Larkin]

On Thu, 12 May 2022 10:43:14 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

Arie de Muijnck wrote:
On 2022-05-12 00:30, John Larkin wrote:

I conjecture (ie guess) that base current makes collector current down
at the single-electron level. 1 pA is just 6 milion electrons per
second.

AFAIK, it\'s not the base current but base voltage that controls the
collector current. The base current is just an unfortunate side effect.
The relation between them happens to be rather constant, hence the idea
that hfe is the main factor. Ideally, the base \'leakage\' could be so low
that base current electrons can be counted. In that case, would the much
higher collector current come in packets?

Arie

Yup, a BJT is a transconductance device with a loss mechanism
(recombination in the base region) that produces leakage current. IIRC
Mikko Kiviranta or somebody said that the beta of a BFP650 goes up to
above 10000 at low temperature.

Cheers

Phil Hobbs

A transistor has c-b leakage, Is of the c-b diode, so turns itself on
with the base open. Spice at least suggests that any amount of added
base current increases collector current.

That said, I don\'t understand this:

Version 4
SHEET 1 880 680
WIRE 288 80 272 80
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WINDOW 0 -8 51 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 1
TEXT 56 144 Left 2 !.tran 2
TEXT 528 184 Left 2 !.op abstol 1e-18
TEXT 528 216 Left 2 !.op gmin 1e-18
TEXT 0 56 Left 2 ;Low current NPN test
TEXT 32 88 Left 2 ;JL May 12 2022


--

If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon

 

[Don]

Phil Hobbs wrote:

Don wrote:
Arie de Muijnck wrote:
John Larkin wrote:

I conjecture (ie guess) that base current makes collector current down
at the single-electron level. 1 pA is just 6 milion electrons per
second.

AFAIK, it\'s not the base current but base voltage that controls the
collector current. The base current is just an unfortunate side effect.
The relation between them happens to be rather constant, hence the idea
that hfe is the main factor. Ideally, the base \'leakage\' could be so low
that base current electrons can be counted. In that case, would the much
higher collector current come in packets?

Good point. You must be within the active region to use the hybrid model
to ignore transconductance.

Don\'t ever ignore transconductance.

\"Hybrid\" (as used by me above) is arguably ambiguous. \"Hybrid
equivalent\" puts a finer point on it. And it indeed ignores
transconductance:

https://upload.wikimedia.org/wikipedia/commons/9/9f/BJT_h-parameters_(generalised).svg

Danke,

--
Don, KB7RPU, https://www.qsl.net/kb7rpu
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.

 

[Phil Hobbs]

Don wrote:

Phil Hobbs wrote:
Don wrote:
Arie de Muijnck wrote:
John Larkin wrote:

I conjecture (ie guess) that base current makes collector current down
at the single-electron level. 1 pA is just 6 milion electrons per
second.

AFAIK, it\'s not the base current but base voltage that controls the
collector current. The base current is just an unfortunate side effect.
The relation between them happens to be rather constant, hence the idea
that hfe is the main factor. Ideally, the base \'leakage\' could be so low
that base current electrons can be counted. In that case, would the much
higher collector current come in packets?

Good point. You must be within the active region to use the hybrid model
to ignore transconductance.

Don\'t ever ignore transconductance.

\"Hybrid\" (as used by me above) is arguably ambiguous. \"Hybrid
equivalent\" puts a finer point on it. And it indeed ignores
transconductance:

https://upload.wikimedia.org/wikipedia/commons/9/9f/BJT_h-parameters_(generalised).svg

Danke,

Of course it does. That\'s why nobody ever uses it for anything real
AFAICT. The only reference I ever make to the h model is the current
gain, because it\'s easy to keep the distinction between small-signal
(h_FE) and large-signal (H_FE) straight.

One could use upper- and lowercase beta, but uppercase beta is
indistinguishable from B.

You can turn LEDs on and off ignoring g_M, or make a rule-of-thumb
single-ended CE amplifier with emitter degeneration. For anything
differential, you use g_M for the design and beta for the sanity check.

Beta is a useful number, mostly because it warns you about things you
can\'t do, but even in beta-graded parts it varies by a factor of 2,
whereas the transconductance of any two BJTs at the same collector
current and same temperature, of whatever size, of whatever make,
matches to a tiny fraction of 1%, at least at collector currents where
beta is vaguely reasonable.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Phil Hobbs]

John Larkin wrote:

On Thu, 12 May 2022 10:43:14 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Arie de Muijnck wrote:
On 2022-05-12 00:30, John Larkin wrote:

I conjecture (ie guess) that base current makes collector current down
at the single-electron level. 1 pA is just 6 milion electrons per
second.

AFAIK, it\'s not the base current but base voltage that controls the
collector current. The base current is just an unfortunate side effect.
The relation between them happens to be rather constant, hence the idea
that hfe is the main factor. Ideally, the base \'leakage\' could be so low
that base current electrons can be counted. In that case, would the much
higher collector current come in packets?

Arie

Yup, a BJT is a transconductance device with a loss mechanism
(recombination in the base region) that produces leakage current. IIRC
Mikko Kiviranta or somebody said that the beta of a BFP650 goes up to
above 10000 at low temperature.

Cheers

Phil Hobbs

A transistor has c-b leakage, Is of the c-b diode, so turns itself on
with the base open. Spice at least suggests that any amount of added
base current increases collector current.

That said, I don\'t understand this:
snip

I went into the control panel and set chgtol and absolute current
tolerance to 1E-18, and it works fine.

Hopefully JT is smiling indulgently somewhere.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[whit3rd]

On Wednesday, May 11, 2022 at 3:30:14 PM UTC-7, John Larkin wrote:

I conjecture (ie guess) that base current makes collector current down
at the single-electron level. 1 pA is just 6 milion electrons per
second.

The other numbers are important. A single-electron level is noise
(recombination noise) in a semiconductor of any useful size.
Transistor base and emitter contacts for most packages are dozens of
microns, so discrete transistor volumes are on the order of 5E-5 cubic
centimeters. At 1.4 x 10E10 charge carriers per cc, for silicon, there\'s
mobile electrons and holes by the thousands in a transistor-size
piece of nonconducting (undoped) silicon. A doped transistor has... more.

It takes sizeable base charge to get above the noise.

 

[John Larkin]

On Thu, 12 May 2022 15:01:06 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin wrote:
On Thu, 12 May 2022 10:43:14 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Arie de Muijnck wrote:
On 2022-05-12 00:30, John Larkin wrote:

I conjecture (ie guess) that base current makes collector current down
at the single-electron level. 1 pA is just 6 milion electrons per
second.

AFAIK, it\'s not the base current but base voltage that controls the
collector current. The base current is just an unfortunate side effect.
The relation between them happens to be rather constant, hence the idea
that hfe is the main factor. Ideally, the base \'leakage\' could be so low
that base current electrons can be counted. In that case, would the much
higher collector current come in packets?

Arie

Yup, a BJT is a transconductance device with a loss mechanism
(recombination in the base region) that produces leakage current. IIRC
Mikko Kiviranta or somebody said that the beta of a BFP650 goes up to
above 10000 at low temperature.

Cheers

Phil Hobbs

A transistor has c-b leakage, Is of the c-b diode, so turns itself on
with the base open. Spice at least suggests that any amount of added
base current increases collector current.

That said, I don\'t understand this:
snip

I went into the control panel and set chgtol and absolute current
tolerance to 1E-18, and it works fine.

Hopefully JT is smiling indulgently somewhere.

Cheers

Phil Hobbs

What I don\'t understand is why the sine wave current source doesn\'t
make a sine wave of current.

--

If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon

 

[whit3rd]

On Thursday, May 12, 2022 at 1:20:11 PM UTC-7, John Larkin wrote:

John Larkin wrote:

A transistor has c-b leakage, Is of the c-b diode, so turns itself on
with the base open. Spice at least suggests that any amount of added
base current increases collector current.

What I don\'t understand is why the sine wave current source doesn\'t
make a sine wave of current.

The base sees leakage plus a sinewave. How could that sum be
proportional to a sinewave, when your applied signal is a sine,
but leakage is a non-negligible constant?

 

[Phil Hobbs]

John Larkin wrote:

On Thu, 12 May 2022 15:01:06 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin wrote:
On Thu, 12 May 2022 10:43:14 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Arie de Muijnck wrote:
On 2022-05-12 00:30, John Larkin wrote:

I conjecture (ie guess) that base current makes collector current down
at the single-electron level. 1 pA is just 6 milion electrons per
second.

AFAIK, it\'s not the base current but base voltage that controls the
collector current. The base current is just an unfortunate side effect.
The relation between them happens to be rather constant, hence the idea
that hfe is the main factor. Ideally, the base \'leakage\' could be so low
that base current electrons can be counted. In that case, would the much
higher collector current come in packets?

Arie

Yup, a BJT is a transconductance device with a loss mechanism
(recombination in the base region) that produces leakage current. IIRC
Mikko Kiviranta or somebody said that the beta of a BFP650 goes up to
above 10000 at low temperature.

Cheers

Phil Hobbs

A transistor has c-b leakage, Is of the c-b diode, so turns itself on
with the base open. Spice at least suggests that any amount of added
base current increases collector current.

That said, I don\'t understand this:
snip

I went into the control panel and set chgtol and absolute current
tolerance to 1E-18, and it works fine.

Hopefully JT is smiling indulgently somewhere.

Cheers

Phil Hobbs

What I don\'t understand is why the sine wave current source doesn\'t
make a sine wave of current.

Right, but if you hack at the control panel as above, it does.

See <https://electrooptical.net/www/sed/JLpuzzle.png>.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[server]

On Thu, 12 May 2022 13:34:27 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:

On Thursday, May 12, 2022 at 1:20:11 PM UTC-7, John Larkin wrote:

John Larkin wrote:

A transistor has c-b leakage, Is of the c-b diode, so turns itself on
with the base open. Spice at least suggests that any amount of added
base current increases collector current.

What I don\'t understand is why the sine wave current source doesn\'t
make a sine wave of current.

The base sees leakage plus a sinewave. How could that sum be
proportional to a sinewave, when your applied signal is a sine,
but leakage is a non-negligible constant?

A current source shouldn\'t care about its load. It should make its
programmed current.



--

Anybody can count to one.

- Robert Widlar

 

[server]

On Thu, 12 May 2022 16:41:47 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin wrote:
On Thu, 12 May 2022 15:01:06 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin wrote:
On Thu, 12 May 2022 10:43:14 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Arie de Muijnck wrote:
On 2022-05-12 00:30, John Larkin wrote:

I conjecture (ie guess) that base current makes collector current down
at the single-electron level. 1 pA is just 6 milion electrons per
second.

AFAIK, it\'s not the base current but base voltage that controls the
collector current. The base current is just an unfortunate side effect.
The relation between them happens to be rather constant, hence the idea
that hfe is the main factor. Ideally, the base \'leakage\' could be so low
that base current electrons can be counted. In that case, would the much
higher collector current come in packets?

Arie

Yup, a BJT is a transconductance device with a loss mechanism
(recombination in the base region) that produces leakage current. IIRC
Mikko Kiviranta or somebody said that the beta of a BFP650 goes up to
above 10000 at low temperature.

Cheers

Phil Hobbs

A transistor has c-b leakage, Is of the c-b diode, so turns itself on
with the base open. Spice at least suggests that any amount of added
base current increases collector current.

That said, I don\'t understand this:
snip

I went into the control panel and set chgtol and absolute current
tolerance to 1E-18, and it works fine.

Hopefully JT is smiling indulgently somewhere.

Cheers

Phil Hobbs

What I don\'t understand is why the sine wave current source doesn\'t
make a sine wave of current.


Right, but if you hack at the control panel as above, it does.

See <https://electrooptical.net/www/sed/JLpuzzle.png>.

Cheers

Phil Hobbs

I can get the current source to make a sine wave if I skip the initial
operating point solution, uic, with your spice settings, but the
collector current is goofy, a 250 Hz triangle.

One issue is maybe the roughly negative 1 gigavolt swing on the base.



--

Anybody can count to one.

- Robert Widlar

 

[Phil Hobbs]

jlarkin@highlandsniptechnology.com wrote:

On Thu, 12 May 2022 16:41:47 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin wrote:
On Thu, 12 May 2022 15:01:06 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin wrote:
On Thu, 12 May 2022 10:43:14 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Arie de Muijnck wrote:
On 2022-05-12 00:30, John Larkin wrote:

I conjecture (ie guess) that base current makes collector current down
at the single-electron level. 1 pA is just 6 milion electrons per
second.

AFAIK, it\'s not the base current but base voltage that controls the
collector current. The base current is just an unfortunate side effect.
The relation between them happens to be rather constant, hence the idea
that hfe is the main factor. Ideally, the base \'leakage\' could be so low
that base current electrons can be counted. In that case, would the much
higher collector current come in packets?

Arie

Yup, a BJT is a transconductance device with a loss mechanism
(recombination in the base region) that produces leakage current. IIRC
Mikko Kiviranta or somebody said that the beta of a BFP650 goes up to
above 10000 at low temperature.

Cheers

Phil Hobbs

A transistor has c-b leakage, Is of the c-b diode, so turns itself on
with the base open. Spice at least suggests that any amount of added
base current increases collector current.

That said, I don\'t understand this:
snip

I went into the control panel and set chgtol and absolute current
tolerance to 1E-18, and it works fine.

Hopefully JT is smiling indulgently somewhere.


What I don\'t understand is why the sine wave current source doesn\'t
make a sine wave of current.


Right, but if you hack at the control panel as above, it does.

See <https://electrooptical.net/www/sed/JLpuzzle.png>.


I can get the current source to make a sine wave if I skip the initial
operating point solution, uic, with your spice settings, but the
collector current is goofy, a 250 Hz triangle.

One issue is maybe the roughly negative 1 gigavolt swing on the base.

Nice and well-behaved for me, just tightening up all the tolerances
(including some on the compression page of the control panel, which
isn\'t shown on the screen shots).

<https://electrooptical.net/www/sed/JLpuzzle2.png>

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[John S]

On 5/12/2022 3:19 PM, John Larkin wrote:

On Thu, 12 May 2022 15:01:06 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin wrote:
On Thu, 12 May 2022 10:43:14 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Arie de Muijnck wrote:
On 2022-05-12 00:30, John Larkin wrote:

I conjecture (ie guess) that base current makes collector current down
at the single-electron level. 1 pA is just 6 milion electrons per
second.

AFAIK, it\'s not the base current but base voltage that controls the
collector current. The base current is just an unfortunate side effect.
The relation between them happens to be rather constant, hence the idea
that hfe is the main factor. Ideally, the base \'leakage\' could be so low
that base current electrons can be counted. In that case, would the much
higher collector current come in packets?

Arie

Yup, a BJT is a transconductance device with a loss mechanism
(recombination in the base region) that produces leakage current. IIRC
Mikko Kiviranta or somebody said that the beta of a BFP650 goes up to
above 10000 at low temperature.

Cheers

Phil Hobbs

A transistor has c-b leakage, Is of the c-b diode, so turns itself on
with the base open. Spice at least suggests that any amount of added
base current increases collector current.

That said, I don\'t understand this:
snip

I went into the control panel and set chgtol and absolute current
tolerance to 1E-18, and it works fine.

Hopefully JT is smiling indulgently somewhere.

Cheers

Phil Hobbs

What I don\'t understand is why the sine wave current source doesn\'t
make a sine wave of current.

Works great!

Version 4
SHEET 1 880 680
WIRE -96 64 -176 64
WIRE 288 80 272 80
WIRE 304 80 288 80
WIRE 416 80 384 80
WIRE -176 128 -176 64
WIRE -96 128 -96 64
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WIRE 176 176 144 176
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SYMATTR InstName R2
SYMATTR Value 1g
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TEXT 528 184 Left 2 !.op abstol 1e-18
TEXT 528 216 Left 2 !.op gmin 1e-18
TEXT 0 56 Left 2 ;Low current NPN test
TEXT 32 88 Left 2 ;JL May 12 2022

 

[Hul Tytus]

Piotr you might look at the hc cmos series. They will operate in
the 1 volt range with the expected lower current. One maker spoke
of characterizing their devices at one something volts.
I experimented with those supply voltages for devices
working in the 100k cps area and all seemed pheasable.

Hul


Piotr Wyderski <bombald@protonmail.com> wrote:

John Larkin wrote:

There is a niche of building oscillators that run at very low supply
voltages, ballpark 10 mV. I think jfets do pretty good.

Yes, there are several interesting examples. The lowest voltage I know
of is 20mV. But in this off-time research application related to the
recent CeraCharge purchase I am trying to minimize current consumption,
not voltage. It can stop oscillating at 1.2V, no problem with that. But
if the current could be as low as 20nA, that would be something.

Best regards, Piotr

 

[server]

On Fri, 13 May 2022 21:45:10 -0500, John S <Sophi.2@invalid.org>
wrote:

On 5/12/2022 3:19 PM, John Larkin wrote:
On Thu, 12 May 2022 15:01:06 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin wrote:
On Thu, 12 May 2022 10:43:14 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Arie de Muijnck wrote:
On 2022-05-12 00:30, John Larkin wrote:

I conjecture (ie guess) that base current makes collector current down
at the single-electron level. 1 pA is just 6 milion electrons per
second.

AFAIK, it\'s not the base current but base voltage that controls the
collector current. The base current is just an unfortunate side effect.
The relation between them happens to be rather constant, hence the idea
that hfe is the main factor. Ideally, the base \'leakage\' could be so low
that base current electrons can be counted. In that case, would the much
higher collector current come in packets?

Arie

Yup, a BJT is a transconductance device with a loss mechanism
(recombination in the base region) that produces leakage current. IIRC
Mikko Kiviranta or somebody said that the beta of a BFP650 goes up to
above 10000 at low temperature.

Cheers

Phil Hobbs

A transistor has c-b leakage, Is of the c-b diode, so turns itself on
with the base open. Spice at least suggests that any amount of added
base current increases collector current.

That said, I don\'t understand this:
snip

I went into the control panel and set chgtol and absolute current
tolerance to 1E-18, and it works fine.

Hopefully JT is smiling indulgently somewhere.

Cheers

Phil Hobbs

What I don\'t understand is why the sine wave current source doesn\'t
make a sine wave of current.



Works great!

Not really. If yoy disconnect the base, the current source still
swings +- 100 mv. That depends on some Spice settings.

Version 4
SHEET 1 880 680
WIRE -96 64 -176 64
WIRE 288 80 272 80
WIRE 304 80 288 80
WIRE 416 80 384 80
WIRE -176 128 -176 64
WIRE -96 128 -96 64
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WIRE 416 144 416 80
WIRE 176 176 144 176
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WIRE 144 208 144 176
WIRE -176 224 -176 208
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SYMATTR Value SINE(0 100f 1)
SYMBOL res 400 64 R90
WINDOW 0 -8 51 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 1
SYMBOL current -176 208 R180
WINDOW 0 54 35 Left 2
WINDOW 3 24 0 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName I2
SYMATTR Value SINE(0 100f 1)
SYMBOL res -112 112 R0
SYMATTR InstName R2
SYMATTR Value 1g
TEXT 56 144 Left 2 !.tran 2
TEXT 528 184 Left 2 !.op abstol 1e-18
TEXT 528 216 Left 2 !.op gmin 1e-18
TEXT 0 56 Left 2 ;Low current NPN test
TEXT 32 88 Left 2 ;JL May 12 2022

--

Anybody can count to one.

- Robert Widlar

 

[piglet]

On 14/05/2022 07:04, Hul Tytus wrote:

Piotr you might look at the hc cmos series. They will operate in
the 1 volt range with the expected lower current. One maker spoke
of characterizing their devices at one something volts.
I experimented with those supply voltages for devices
working in the 100k cps area and all seemed pheasable.

Hul

Yes, I actually experienced HC cmos retaining stored latch states down
into tens of millivolts region. However to make any kind of oscillator
means passing slowly through a linear region and current consumption
will shoot up. To make an oscillator a discrete design with high value
series resistors might be better, this draws an average 10nA to make
narrow pulses every 8-9 secs...

Version 4
SHEET 1 1160 680
WIRE 32 -640 -208 -640
WIRE 336 -640 32 -640
WIRE 864 -640 336 -640
WIRE 336 -592 336 -640
WIRE 32 -544 32 -640
WIRE 864 -464 864 -640
WIRE 336 -432 336 -512
WIRE 576 -432 336 -432
WIRE 336 -368 336 -432
WIRE 32 -320 32 -464
WIRE 272 -320 32 -320
WIRE 576 -304 576 -432
WIRE 32 -240 32 -320
WIRE 336 -192 336 -272
WIRE 576 -144 576 -240
WIRE 576 -144 400 -144
WIRE 576 -80 576 -144
WIRE 32 -16 32 -176
WIRE 336 -16 336 -96
WIRE 336 -16 32 -16
WIRE 864 32 864 -384
WIRE -208 64 -208 -640
WIRE 336 80 336 -16
WIRE 432 80 336 80
WIRE 800 80 512 80
WIRE 336 176 336 80
WIRE -208 288 -208 144
WIRE 336 288 336 256
WIRE 336 288 -208 288
WIRE 576 288 576 0
WIRE 576 288 336 288
WIRE 864 288 864 128
WIRE 864 288 576 288
WIRE -208 320 -208 288
FLAG -208 320 0
SYMBOL voltage -208 48 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 1.3
SYMBOL pnp 400 -96 R180
SYMATTR InstName Q1
SYMATTR Value 2N3906
SYMBOL npn 272 -368 R0
SYMATTR InstName Q2
SYMATTR Value 2N3904
SYMBOL res 320 -608 R0
SYMATTR InstName R1
SYMATTR Value 10Meg
SYMBOL res 560 -96 R0
SYMATTR InstName R3
SYMATTR Value 100Meg
SYMBOL res 16 -560 R0
SYMATTR InstName R4
SYMATTR Value 100Meg
SYMBOL cap 16 -240 R0
SYMATTR InstName C1
SYMATTR Value 100n
SYMBOL cap 560 -304 R0
SYMATTR InstName C2
SYMATTR Value 100n
SYMBOL npn 800 32 R0
SYMATTR InstName Q3
SYMATTR Value 2N3904
SYMBOL res 848 -480 R0
SYMATTR InstName R5
SYMATTR Value 10Meg
SYMBOL res 320 160 R0
SYMATTR InstName R6
SYMATTR Value 10Meg
SYMBOL res 528 64 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R2
SYMATTR Value 10Meg
TEXT -242 360 Left 2 !.tran 100
TEXT 928 336 Left 2 ;EPW SED MAY 2022
TEXT 928 288 Left 2 ;Nano power pulser



piglet

 

[Hul Tytus]

Good point for an osicilator. The 10\'s of millivolts range you mention
is an interesting area.

Hul


piglet <erichpwagner@hotmail.com> wrote:

On 14/05/2022 07:04, Hul Tytus wrote:
Piotr you might look at the hc cmos series. They will operate in
the 1 volt range with the expected lower current. One maker spoke
of characterizing their devices at one something volts.
I experimented with those supply voltages for devices
working in the 100k cps area and all seemed pheasable.

Hul


Yes, I actually experienced HC cmos retaining stored latch states down
into tens of millivolts region. However to make any kind of oscillator
means passing slowly through a linear region and current consumption
will shoot up. To make an oscillator a discrete design with high value
series resistors might be better, this draws an average 10nA to make
narrow pulses every 8-9 secs...

Version 4
SHEET 1 1160 680
WIRE 32 -640 -208 -640
WIRE 336 -640 32 -640
WIRE 864 -640 336 -640
WIRE 336 -592 336 -640
WIRE 32 -544 32 -640
WIRE 864 -464 864 -640
WIRE 336 -432 336 -512
WIRE 576 -432 336 -432
WIRE 336 -368 336 -432
WIRE 32 -320 32 -464
WIRE 272 -320 32 -320
WIRE 576 -304 576 -432
WIRE 32 -240 32 -320
WIRE 336 -192 336 -272
WIRE 576 -144 576 -240
WIRE 576 -144 400 -144
WIRE 576 -80 576 -144
WIRE 32 -16 32 -176
WIRE 336 -16 336 -96
WIRE 336 -16 32 -16
WIRE 864 32 864 -384
WIRE -208 64 -208 -640
WIRE 336 80 336 -16
WIRE 432 80 336 80
WIRE 800 80 512 80
WIRE 336 176 336 80
WIRE -208 288 -208 144
WIRE 336 288 336 256
WIRE 336 288 -208 288
WIRE 576 288 576 0
WIRE 576 288 336 288
WIRE 864 288 864 128
WIRE 864 288 576 288
WIRE -208 320 -208 288
FLAG -208 320 0
SYMBOL voltage -208 48 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 1.3
SYMBOL pnp 400 -96 R180
SYMATTR InstName Q1
SYMATTR Value 2N3906
SYMBOL npn 272 -368 R0
SYMATTR InstName Q2
SYMATTR Value 2N3904
SYMBOL res 320 -608 R0
SYMATTR InstName R1
SYMATTR Value 10Meg
SYMBOL res 560 -96 R0
SYMATTR InstName R3
SYMATTR Value 100Meg
SYMBOL res 16 -560 R0
SYMATTR InstName R4
SYMATTR Value 100Meg
SYMBOL cap 16 -240 R0
SYMATTR InstName C1
SYMATTR Value 100n
SYMBOL cap 560 -304 R0
SYMATTR InstName C2
SYMATTR Value 100n
SYMBOL npn 800 32 R0
SYMATTR InstName Q3
SYMATTR Value 2N3904
SYMBOL res 848 -480 R0
SYMATTR InstName R5
SYMATTR Value 10Meg
SYMBOL res 320 160 R0
SYMATTR InstName R6
SYMATTR Value 10Meg
SYMBOL res 528 64 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R2
SYMATTR Value 10Meg
TEXT -242 360 Left 2 !.tran 100
TEXT 928 336 Left 2 ;EPW SED MAY 2022
TEXT 928 288 Left 2 ;Nano power pulser

> piglet

 

[Piotr Wyderski]

piglet wrote:

Yes, I actually experienced HC cmos retaining stored latch states down
into tens of millivolts region. However to make any kind of oscillator
means passing slowly through a linear region and current consumption
will shoot up. To make an oscillator a discrete design with high value
series resistors might be better, this draws an average 10nA to make
narrow pulses every 8-9 secs...

Nice, your edges are super sharp. Here is mine, sort of 1us pulses at
14Hz with 30nA average at 3V. The perhaps interesting part is the narrow
pulse generator: the pulse duration is limited by the energy stored in
C2, as the discharging cycle itself is orders of magnitude longer. With
R7 I can specify any reasonable duration and it comes at no additional
energy cost, as the energy to be dissipated has already come through R4.

On the downside, I got stuck here: no idea how to transform the 100mV
V_OUT pulses into the full VDD swing without a fancy 100mV Vth
transistor and still keep the average power consumption low. The bias
network for a differential amplifier or a common base stage will burn
hundreds of times more power than the oscillator. Inductors don\'t seem
to help here.

Best regards, Piotr


Version 4
SHEET 1 880 680
WIRE -176 -336 -256 -336
WIRE -48 -336 -96 -336
WIRE 0 -336 -48 -336
WIRE 192 -336 80 -336
WIRE 368 -336 192 -336
WIRE 576 -336 368 -336
WIRE -48 -320 -48 -336
WIRE 368 -272 368 -336
WIRE -48 -240 -48 -256
WIRE 192 -224 192 -336
WIRE 576 -192 576 -336
WIRE 368 -176 368 -192
WIRE 528 -176 368 -176
WIRE -256 -160 -256 -336
WIRE 368 -160 368 -176
WIRE 192 -80 192 -144
WIRE 192 -80 144 -80
WIRE 288 -80 192 -80
WIRE 320 -80 288 -80
WIRE 576 -80 576 -96
WIRE 688 -80 576 -80
WIRE -256 -64 -256 -80
WIRE 576 -64 576 -80
WIRE 192 -48 192 -80
WIRE 288 -32 288 -80
WIRE 192 32 192 16
WIRE 368 32 368 -64
WIRE 576 32 576 16
WIRE 288 80 288 48
WIRE 688 160 688 -80
WIRE 688 160 336 160
WIRE 288 192 288 176
WIRE 288 192 144 192
WIRE 288 208 288 192
WIRE 288 304 288 288
FLAG -256 -64 0
FLAG -48 -240 0
FLAG 368 32 0
FLAG 576 32 0
FLAG 192 32 0
FLAG 144 -80 V_C2
FLAG 288 304 0
FLAG 144 192 V_OUT
SYMBOL voltage -256 -176 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 3v
SYMBOL res -16 -320 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R1
SYMATTR Value 1m
SYMBOL cap -64 -320 R0
SYMATTR InstName C1
SYMATTR Value 100n
SYMBOL res -192 -320 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R2
SYMATTR Value 1m
SYMBOL nmos 320 -160 R0
SYMATTR InstName M1
SYMATTR Value BSS123
SYMBOL res 352 -288 R0
SYMATTR InstName R3
SYMATTR Value 47Meg
SYMBOL res 176 -240 R0
SYMATTR InstName R4
SYMATTR Value 200Meg
SYMBOL pmos 528 -96 M180
SYMATTR InstName M2
SYMATTR Value BSS84
SYMBOL res 560 -80 R0
SYMATTR InstName R5
SYMATTR Value 15Meg
SYMBOL cap 176 -48 R0
SYMATTR InstName C2
SYMATTR Value 470p
SYMBOL nmos 336 80 M0
SYMATTR InstName M3
SYMATTR Value BSS123
SYMBOL res 272 -48 R0
SYMATTR InstName R6
SYMATTR Value 1m
SYMBOL res 272 192 R0
SYMATTR InstName R7
SYMATTR Value 330
TEXT -280 16 Left 2 !.ic V(V_C2)=0
TEXT -290 328 Left 2 !.tran 1

 

[Piotr Wyderski]

piglet wrote:

To make an oscillator a discrete design with high value
series resistors might be better, this draws an average 10nA to make
narrow pulses every 8-9 secs...

After some prototyping I can confirm, your UJT-emulating circuit wins
hands down. I removed R6, R2, Q3 and R5, changed C1 and C2 to 470p and
coupled to the C2 discharge energy via a small transformer, getting
beautiful 1us spikes @28Hz. Thank you, Piglet!

Best regards, Piotr

 

[John Larkin]

On Sat, 14 May 2022 19:03:40 +0100, piglet <erichpwagner@hotmail.com>
wrote:

On 14/05/2022 07:04, Hul Tytus wrote:
Piotr you might look at the hc cmos series. They will operate in
the 1 volt range with the expected lower current. One maker spoke
of characterizing their devices at one something volts.
I experimented with those supply voltages for devices
working in the 100k cps area and all seemed pheasable.

Hul


Yes, I actually experienced HC cmos retaining stored latch states down
into tens of millivolts region. However to make any kind of oscillator
means passing slowly through a linear region and current consumption
will shoot up. To make an oscillator a discrete design with high value
series resistors might be better, this draws an average 10nA to make
narrow pulses every 8-9 secs...

I want an LED blinker to show that a high-voltage power supply is
still dangerous. It should discharge the supply at some low current
and blink from, say, 1400 volts down to maybe 40.

A variant of your circuit might work. Charge a cap through a string of
depletion fets and modify your thing with a zener between emitters.

--

If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon

 

[whit3rd]

On Monday, May 23, 2022 at 10:19:30 AM UTC-7, John Larkin wrote:

I want an LED blinker to show that a high-voltage power supply is
still dangerous. It should discharge the supply at some low current
and blink from, say, 1400 volts down to maybe 40.

So, a series string of fifteen current-limit diodes running a capacitor-
diac-LED blinkielight? S-272 seems suitable

<https://www.mouser.com/datasheet/2/362/P22-23-CRD-1729293.pdf>