What's a Good Sub for a 45V Zener?

Watson A.Name \"Watt Sun · Mar 25, 2004

Pooh Bear wrote:

"Watson A.Name - \"Watt Sun, the Dark Remover\"" wrote:

"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> wrote in message
news:7jdr5054bntpufeta9nvpnkn1eqebi967i@4ax.com...

On Sun, 21 Mar 2004 09:43:13 -0500, the renowned "David"
dkuhajda@locl.net.spam> wrote:

Why not use one of the simple, cheap ics already made for the purpose

of

voltage conversion?

Or 3 of those 15v smoke alarm batteries.

Might be cheaper to snap together 5 9V batteries. ;-)
570mA @ 45V for a mere $7.

Yeah, I did; see my other followup.

There's no reason you can't use the E-B junctions and they should be
very consistent within a lot of transistors, but don't try to use the
transistors as transistors again afterward.

I usually clip off the collector lead and wrap it around the base lead.
Takes care of that problem. I just wonder if I can get a Base to
Collector junction to reliably zener or breakdown. One time I rectified
and filtered 120VAC to get about 170VDC, and I put that thru a 150k or
so resistor and across some transistors to see what voltage they would
break down at. Well, as soon as I connected the meter leads, the things
oscillated so nasty that every channel on the TV was nothing but hum
bars and buzzing in the audio. Wow, what a jammer.

You are a complete TWAT !

Gee, who put a burr under your blanket?? Pooh Bear never talked like that!

If you want a cheap 'zener' - actually an avalanche breakdown device - you
reverse bias the B-E junction !

Should typically give you 7 Volts.

Yeah, I do that all the time with some junky old transistors I have, but
it will take 6 or 7 of them to do the job (which is no problem since I
still have a few thousand left). But to save board space I thought that
I might be able to do it with just one.

Seems you guys fall into the very worst of the 'nerds' category - trying to
make bits you bought cheap work that were never intended to be used that way
- good luck to you !

Actually I received the device I purchased from the facory last night.
It works okay, but it requires 5 new 9V (PP3) batteries every time I
have to replace the "45V battery". I figured I'd save a bundle by using
4 AA cells and an inverter, but I didn't think I'd run into as much flak
about it as I have.

I'll say good luck to planks of wood too.

Ok, termite! I see you crawled out of the woodwork..

> Graham

Watson A.Name \"Watt Sun · Mar 25, 2004

Mark Zenier wrote:

"Watson A.Name - \"Watt Sun, the Dark Remover\"" <NOSPAM@dslextreme.com> wrote in message news:<1060gafnavf2va1@corp.supernews.com>...

"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:405E9B54.E45BE0D8@hotmail.com...

"Watson A.Name - \"Watt Sun, the Dark Remover\"" wrote:

TL431

Yeah, i thought about that. But they're good only up to 36V.

But what's the end of life voltage of a 45 volt battery? I'd expect
a circuit that uses them to work down to 30 volts or so.

I thought about that, too. But the adjustment won't work much below
45V, probably because the meter is designed to be like the telco central
office and put out 48V or close to it. If anything it needs a bit more
than 45V to be on the safe side.

This morning I got the 45V battery eliminator and installed the five 9V
batteries on it, and put it in the meter. I tested it out and it works
just like it's supposed to, the meter zero's and gives good readings on
the telephone lines.

> Mark Zenier mzenier@eskimo.com

Frank Bemelman · Mar 25, 2004

"Jim Thompson" <thegreatone@example.com> schreef in bericht
news:6eu36095q3mgv1j3rod0hikgrro3058t5a@4ax.com...

Throughout the history of this great country there have actually
been people of only two political persuasions: fighters and cowards.
WE MUST NOT LET THE LATTER PREVAIL IN THE NEXT ELECTION!

Pathetic.

--
Thanks, Frank.
(remove 'x' and 'invalid' when replying by email)

Emoneg · Mar 25, 2004

"Watson A.Name "Watt Sun - the Dark Remover"" <NOSPAM@dslextreme.com>
wrote in message news:c3ssvu$6etug$1@hades.csu.net...
|
| I d/l'd it (4 megs in 2.5 seconds) on my PC at work and installed it
| just so I could print out your schematic. It works but I don't know
how
| to use it.
|
| But I see on the schem that there is a circle with VREF 2.5V by it.
| Well, that doesn'ttell me anything about how to do it in the real
world.
| One presumes that it really should be a TL431 with a resistor to V+,
| but there's nothing there that tells one that.
|
| What _IS_ this MSWITCH symbol?? A power FET? Surely you don't expect
| me to sit there flipping a switch a hundred thousand times a
second!?!?!
| DOH! Why are D1 and D2 in series?? Etc., etc., etc...

Well... I did suggest that you download a datasheet for a UCC380X/UC384X
from Ti.

Somewhere in there they give a block diagram of its internals. You might
be able to match things up.

.........

DNA

Emoneg · Mar 25, 2004

"Frank Bemelman" <f.bemelmanx@planet.invalid.nl> wrote in message
news:40621885$0$32736$c3e8da3@news.astraweb.com...
| "Jim Thompson" <thegreatone@example.com> schreef in bericht
| news:6eu36095q3mgv1j3rod0hikgrro3058t5a@4ax.com...
| >
| > Throughout the history of this great country there have actually
| > been people of only two political persuasions: fighters and cowards.
| > WE MUST NOT LET THE LATTER PREVAIL IN THE NEXT ELECTION!
|
| Pathetic.
|
| --
| Thanks, Frank.
| (remove 'x' and 'invalid' when replying by email)
|
|

"THERE'S TWO TYPES OF PEOPLE
GOOD PEOPLE AND BASTARDS
NOTHIN ELSE COMES INTO IT."
LEMMY

Unfortunately JIM pays taxes and has a cholostemy bag.
He has also procreated lawyer children.

Fortunately we have the right for a refill....

Pass another bag.

DNA

Jim Thompson · Mar 25, 2004

On Thu, 25 Mar 2004 00:06:17 -0000, "Emoneg" <Emoneg@nothere.com>
wrote:

"Frank Bemelman" <f.bemelmanx@planet.invalid.nl> wrote in message
news:40621885$0$32736$c3e8da3@news.astraweb.com...
| "Jim Thompson" <thegreatone@example.com> schreef in bericht
| news:6eu36095q3mgv1j3rod0hikgrro3058t5a@4ax.com...
|
| > Throughout the history of this great country there have actually
| > been people of only two political persuasions: fighters and cowards.
| > WE MUST NOT LET THE LATTER PREVAIL IN THE NEXT ELECTION!
|
| Pathetic.
|
| Thanks, Frank.
| (remove 'x' and 'invalid' when replying by email)
|
|

"THERE'S TWO TYPES OF PEOPLE
GOOD PEOPLE AND BASTARDS
NOTHIN ELSE COMES INTO IT."
LEMMY

Unfortunately JIM pays taxes and has a cholostemy bag.
He has also procreated lawyer children.

Fortunately we have the right for a refill....

Pass another bag.

DNA

(1) Who gives a fuck what Bemelman thinks? I certainly don't! If
certain folk would not persist in answering him I would be completely
spared his BS.

(2) "Good people and bastards"... indeed the truth!

(3A) "pays taxes", yes, enough to buy a high-end Mercedes every year.

(3B) "cholostomy (sic) bag", no, but it might be handy on long flights
;-)

(3C) "procreated lawyer children", no, although I do have a son-in-law
who is a lawyer... specialty, prosecuting murders.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice

480)460-2350 | |
| E-mail Address at Website Fax

480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

Throughout the history of this great country there have actually
been people of only two political persuasions: fighters and cowards.
WE MUST NOT LET THE LATTER PREVAIL IN THE NEXT ELECTION!

Tim Williams · Mar 25, 2004

"Watson A.Name "Watt Sun - the Dark Remover"" <NOSPAM@dslextreme.com> wrote
in message news:c3ss9p$6eq5v$1@hades.csu.net...

Here's my version of a constant voltage source, using a transistor and
zener:

Add a source follower and a few emitter followers and you'll actually be
able to draw some current from it. ;-)

Tim

--
"I have misplaced my pants." - Homer Simpson | Electronics,
- - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting
and Games: http://webpages.charter.net/dawill/tmoranwms

Frank Bemelman · Mar 25, 2004

"Jim Thompson" <thegreatone@example.com> schreef in bericht
news

094609sf1i3go05f0bmnmqq16akefrph9@4ax.com...

On Thu, 25 Mar 2004 00:06:17 -0000, "Emoneg" <Emoneg@nothere.com
wrote:

(1) Who gives a fuck what Bemelman thinks? I certainly don't! If
certain folk would not persist in answering him I would be completely
spared his BS.

Well, for starters, I care about what I 'think' myself. That's
at least something we seem to have in common. I also care about
what others 'think', something that we don't seem to have in
common.

And if you don't like my BS, perhaps you could filter on
message contents 'Bemelman wrote'. Or wait until I drop
dead instead of your pathetic complaints.

--
Thanks, Frank.
(remove 'x' and 'invalid' when replying by email)

Watson A.Name - \"Watt Su · Mar 25, 2004

"Tim Williams" <tmoranwms@charter.net> wrote in message
news:10649o1fukb1c0e@corp.supernews.com...

"Watson A.Name "Watt Sun - the Dark Remover"" <NOSPAM@dslextreme.com
wrote
in message news:c3ss9p$6eq5v$1@hades.csu.net...
Here's my version of a constant voltage source, using a transistor
and
zener:

Add a source follower and a few emitter followers and you'll actually
be
able to draw some current from it. ;-)

Of all people, you, a toob fan, should know that there are solid state
devices that have an input that doesn't draw any current from the
reference voltage.
Or just use a FET input opamp as the current amplifier. ;-)

Tim

--

Winfield Hill · Mar 25, 2004

Watson A.Name - \"Watt Sun, the Dark Remover\" wrote...

"Pooh Bear" wrote ...

TL431

Yeah, i thought about that. But they're good only up to 36V.

The TL431 can handle up to 100mA, but not at its 36V maximum
rated voltage! Adding a cascode MOSFET allows both going up
to 0.1A and using higher voltages. The MOSFET's gate draws
no current (so it doesn't disturb the voltage divider), and
power MOSFETs come in TO-220 and other handy power packages.

.. o 45V active zener
.. | 2 to 100mA
.. +----------,
.. | irf510 |
.. '--| 37.4k
.. ,->|| |
.. +--||------+ 7V
.. | |
.. | 4.53k
.. \_|_ |
.. / \_________| 2.495V
.. /___\ |
.. | 2.49k
.. | TL431 |
.. --+----------+-----

The TL431 requires 1mA minimum cathode current, which can be
a problem in some designs, but the TLV431 or LMV431 (either
is 80uA min) can be used instead (these have 1.24V references
instead of 2.5V). The TLV and LMV parts also have only 0.15uA
of reference-node current, compared to the TL431's rather high
2uA. They allow using lower divider currents, an important
consideration at high voltages to keep power consumption down.

At high currents the zener-diode shunt-regulator approach is
usually not as attractive as a pass-element regulator. We can
modify the circuit to become a regulator, for 100V shown below.

.. 130 to 170Vdc
.. ---+----------, High-voltage regulator
.. | |
.. 270k |--'
.. | ||<-,
.. +------||--+ irf630
.. | |
.. | +----o +100V
.. | irf610 | to 200mA
.. '--| 1.00M
.. ,->|| |
.. +--||------+ 10V
.. | |
.. | 88.7k
.. \_|_ |
.. / \_________| 1.24V
.. /___\ |
.. | 12.4k
.. | LMV431 |
.. --+----------+-----

With appropriate parts this design can be used to over 1kV. One
can consider adding a current-limit sense resistor and transistor
to the source of the pass FET.

Thanks,
- Win

whill_at_picovolt-dot-com

Winfield Hill · Mar 27, 2004

Winfield Hill wrote...

... the classic zener-diode transistor-feedback high-
voltage regulator circuit, e.g., as shown below.

. +130 - 170Vdc
. Vin Linear High-Voltage Regulator
. ---+---220----, zener-based voltage reference
. | 10W |
. 150k |--'
. | ||<-, Q2
. +------||--+ IRF630
. | , 12V | with heatsink
. +--|<|-----+
. | 1n5242 |
. | +----o +100V
. | 2n5550 | to 100mA
. | Q1 93.1k
. \| |
. |--------+
. v/| |
. | |
. \_|_ 6.81k
. /_\ 6.2V |
. | 1n5234A |
. --+----------+----

This circuit relies on the special properties of zener diodes with
breakdown voltages in the 6-volt region (see AoE pp 332 - 333).

And, forcing ourselves back to the OP's request for a 45-volt zener
diode, we can morph this circuit into an active programmable zener:

.. o-+-------+----------,
.. | | | zener-based 45V active zener
.. | 680 R2
.. v\| | 75.0k
.. |-----+ 2n5550 | operates from 1 to 100mA
.. /| | Q1 |
.. | Q2 \| | Vz = 6.85 (1 + R2/R1) + R2 * 10uA
.. | TIP32 |--------+
.. | v/| |
.. 390-ohm | R1
.. 10W \_|_ 13.7k
.. | /_\ 6.2V |
.. | | 1n5234A |
.. 0-+-------+----------'

Thanks,
- Win

whill_at_picovolt-dot-com

Jim Thompson · Mar 27, 2004

On 26 Mar 2004 13:01:21 -0800, Winfield Hill
<Winfield_member@newsguy.com> wrote:

Winfield Hill wrote...

... the classic zener-diode transistor-feedback high-
voltage regulator circuit, e.g., as shown below.

. +130 - 170Vdc
. Vin Linear High-Voltage Regulator
. ---+---220----, zener-based voltage reference
. | 10W |
. 150k |--'
. | ||<-, Q2
. +------||--+ IRF630
. | , 12V | with heatsink
. +--|<|-----+
. | 1n5242 |
. | +----o +100V
. | 2n5550 | to 100mA
. | Q1 93.1k
. \| |
. |--------+
. v/| |
. | |
. \_|_ 6.81k
. /_\ 6.2V |
. | 1n5234A |
. --+----------+----

This circuit relies on the special properties of zener diodes with
breakdown voltages in the 6-volt region (see AoE pp 332 - 333).

And, forcing ourselves back to the OP's request for a 45-volt zener
diode, we can morph this circuit into an active programmable zener:

. o-+-------+----------,
. | | | zener-based 45V active zener
. | 680 R2
. v\| | 75.0k
. |-----+ 2n5550 | operates from 1 to 100mA
. /| | Q1 |
. | Q2 \| | Vz = 6.85 (1 + R2/R1) + R2 * 10uA
. | TIP32 |--------+
. | v/| |
. 390-ohm | R1
. 10W \_|_ 13.7k
. | /_\ 6.2V |
. | | 1n5234A |
. 0-+-------+----------'

Thanks,
- Win

whill_at_picovolt-dot-com

480)460-2350 | |
| E-mail Address at Website Fax

480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

Throughout the history of this great country there have actually
been people of only two political persuasions: fighters and cowards.
WE MUST NOT LET THE LATTER PREVAIL IN THE NEXT ELECTION!

John Woodgate · Mar 27, 2004

I read in sci.electronics.design that Winfield Hill
<Winfield_member@newsguy.com> wrote (in <c425n101bql@drn.newsguy.com&gt

about 'What's a Good Sub for a 45V Zener?', on Fri, 26 Mar 2004:

And, forcing ourselves back to the OP's request for a 45-volt zener
diode, we can morph this circuit into an active programmable zener:

. o-+-------+----------,
. | | | zener-based 45V active zener
. | 680 R2
. v\| | 75.0k
. |-----+ 2n5550 | operates from 1 to 100mA
. /| | Q1 |
. | Q2 \| | Vz = 6.85 (1 + R2/R1) + R2 * 10uA
. | TIP32 |--------+
. | v/| |
. 390-ohm | R1
. 10W \_|_ 13.7k
. | /_\ 6.2V |
. | | 1n5234A |
. 0-+-------+----------'

What about noise? Would we need a capacitor across the ZD or between
base and emitter of Q1?
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

Winfield Hill · Mar 27, 2004

Jim Thompson wrote...

Winfield Hill wrote:

Winfield Hill wrote...

... the classic zener-diode transistor-feedback high-
voltage regulator circuit, e.g., as shown below.

. +130 - 170Vdc
. Vin Linear High-Voltage Regulator
. ---+---220----, zener-based voltage reference
. | 10W |
. 150k |--'
. | ||<-, Q2
. +------||--+ IRF630
. | , 12V | with heatsink
. +--|<|-----+
. | 1n5242 |
. | +----o +100V
. | 2n5550 | to 100mA
. | Q1 93.1k
. \| |
. |--------+
. v/| |
. | |
. \_|_ 6.81k
. /_\ 6.2V |
. | 1n5234A |
. --+----------+----

This circuit relies on the special properties of zener diodes with
breakdown voltages in the 6-volt region (see AoE pp 332 - 333).

And, forcing ourselves back to the OP's request for a 45-volt zener
diode, we can morph this circuit into an active programmable zener:

. o-+-------+----------,
. | | | zener-based 45V active zener
. | 680 R2
. v\| | 75.0k
. |-----+ 2n5550 | operates from 1 to 100mA
. /| | Q1 |
. | Q2 \| | Vz = 6.85 (1 + R2/R1) + R2 * 10uA
. | TIP32 |--------+
. | v/| |
. 390-ohm | R1
. 10W \_|_ 13.7k
. | /_\ 6.2V |
. | | 1n5234A |
. 0-+-------+----------'

Or use the version I announced on these newsgroups and posted
to the S.E.D/Schematics Page of my website two days ago ;-)

Yep. But your version suffers from much poorer load regulation
because most of the active-zener current goes through the zener
reference and control transistor. Furthermore its Darlington
transistor adds two sets of Vbe variation in series to the zener
reference voltage, whereas mine has only one, in turn biased at
a nearly constant current by the 680-ohm resistor. This results
in much better voltage stability. Moreover, operation at higher
current is made possible by using a power resistor to dissipate
most of the heat (anyone proposing to go over 100mA would want
to add a 6.8k safety resistor in series with Q1's collector).

And of course if operation is limited to modest currents, e.g.,
like yours, the 390-ohm 10W resistor can be eliminated. :&gt

Finally, mine can be programmed to 100V, simply by changing the
resistor ratio and using a common cheap TIP32C power transistor.
Try that with a wimply 2n4401. < score! >

Thanks,
- Win

whill_at_picovolt-dot-com

Jim Thompson · Mar 27, 2004

On 26 Mar 2004 13:55:04 -0800, Winfield Hill
<Winfield_member@newsguy.com> wrote:

Jim Thompson wrote...

Winfield Hill wrote:

Winfield Hill wrote...

... the classic zener-diode transistor-feedback high-
voltage regulator circuit, e.g., as shown below.

. +130 - 170Vdc
. Vin Linear High-Voltage Regulator
. ---+---220----, zener-based voltage reference
. | 10W |
. 150k |--'
. | ||<-, Q2
. +------||--+ IRF630
. | , 12V | with heatsink
. +--|<|-----+
. | 1n5242 |
. | +----o +100V
. | 2n5550 | to 100mA
. | Q1 93.1k
. \| |
. |--------+
. v/| |
. | |
. \_|_ 6.81k
. /_\ 6.2V |
. | 1n5234A |
. --+----------+----

This circuit relies on the special properties of zener diodes with
breakdown voltages in the 6-volt region (see AoE pp 332 - 333).

And, forcing ourselves back to the OP's request for a 45-volt zener
diode, we can morph this circuit into an active programmable zener:

. o-+-------+----------,
. | | | zener-based 45V active zener
. | 680 R2
. v\| | 75.0k
. |-----+ 2n5550 | operates from 1 to 100mA
. /| | Q1 |
. | Q2 \| | Vz = 6.85 (1 + R2/R1) + R2 * 10uA
. | TIP32 |--------+
. | v/| |
. 390-ohm | R1
. 10W \_|_ 13.7k
. | /_\ 6.2V |
. | | 1n5234A |
. 0-+-------+----------'

Or use the version I announced on these newsgroups and posted
to the S.E.D/Schematics Page of my website two days ago ;-)

Yep. But your version suffers from much poorer load regulation
because most of the active-zener current goes through the zener
reference and control transistor. Furthermore its Darlington
transistor adds two sets of Vbe variation in series to the zener
reference voltage, whereas mine has only one, in turn biased at
a nearly constant current by the 680-ohm resistor. This results
in much better voltage stability. Moreover, operation at higher
current is made possible by using a power resistor to dissipate
most of the heat (anyone proposing to go over 100mA would want
to add a 6.8k safety resistor in series with Q1's collector).

And of course if operation is limited to modest currents, e.g.,
like yours, the 390-ohm 10W resistor can be eliminated. :&gt

Finally, mine can be programmed to 100V, simply by changing the
resistor ratio and using a common cheap TIP32C power transistor.
Try that with a wimply 2n4401. < score!

Thanks,
- Win

whill_at_picovolt-dot-com

< score! > my ass!

Learn to observe before you leap. You are *completely wrong* with
"adds two sets of Vbe variation in series to the zener reference
voltage". It's a TL431, not a zener, there is *no* vbe in there,
period.

Change the Darlington to a MOSFET and then there's not even the minute
Ib term.

Did you bother to observe the simulation?

< score! >

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice

480)460-2350 | |
| E-mail Address at Website Fax

480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

Throughout the history of this great country there have actually
been people of only two political persuasions: fighters and cowards.
WE MUST NOT LET THE LATTER PREVAIL IN THE NEXT ELECTION!

Chuck Harris · Mar 27, 2004

Jim Thompson wrote:

. o-+-------+----------,
. | | | zener-based 45V active zener
. | 680 R2
. v\| | 75.0k
. |-----+ 2n5550 | operates from 1 to 100mA
. /| | Q1 |
. | Q2 \| | Vz = 6.85 (1 + R2/R1) + R2 * 10uA
. | TIP32 |--------+
. | v/| |
. 390-ohm | R1
. 10W \_|_ 13.7k
. | /_\ 6.2V |
. | | 1n5234A |
. 0-+-------+----------'

Thanks,
- Win

whill_at_picovolt-dot-com

Or use the version I announced on these newsgroups and posted to the
S.E.D/Schematics Page of my website two days ago ;-)

...Jim Thompson

Golly Jim,

It's not like transistor enhanced zeners haven't been thoroughly
discussed in the popular literature for the past 50 years.

The Q1 half of Win's circuit shows up for discussion in Jacob Millman's
1958 text book. Q2 is just a simple C-E amplifier.

Yours is the same as Millman's, but with a darlington replacing
Q1, and no C-E amplifier stage to boost the power capability.

Ho hum, not what I would call much of a contest of wits ;-)

-Chuck Harris

Jim Thompson · Mar 27, 2004

On Fri, 26 Mar 2004 17:30:17 -0500, Chuck Harris <cfharris@erols.com>
wrote:

Jim Thompson wrote:

. o-+-------+----------,
. | | | zener-based 45V active zener
. | 680 R2
. v\| | 75.0k
. |-----+ 2n5550 | operates from 1 to 100mA
. /| | Q1 |
. | Q2 \| | Vz = 6.85 (1 + R2/R1) + R2 * 10uA
. | TIP32 |--------+
. | v/| |
. 390-ohm | R1
. 10W \_|_ 13.7k
. | /_\ 6.2V |
. | | 1n5234A |
. 0-+-------+----------'

Thanks,
- Win

whill_at_picovolt-dot-com

Or use the version I announced on these newsgroups and posted to the
S.E.D/Schematics Page of my website two days ago ;-)

...Jim Thompson

Golly Jim,

It's not like transistor enhanced zeners haven't been thoroughly
discussed in the popular literature for the past 50 years.

The Q1 half of Win's circuit shows up for discussion in Jacob Millman's
1958 text book. Q2 is just a simple C-E amplifier.

Yours is the same as Millman's, but with a darlington replacing
Q1, and no C-E amplifier stage to boost the power capability.

Ho hum, not what I would call much of a contest of wits ;-)

-Chuck Harris

480)460-2350 | |
| E-mail Address at Website Fax

480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

Throughout the history of this great country there have actually
been people of only two political persuasions: fighters and cowards.
WE MUST NOT LET THE LATTER PREVAIL IN THE NEXT ELECTION!

Jim Thompson · Mar 27, 2004

On Fri, 26 Mar 2004 15:33:34 -0700, Jim Thompson
<thegreatone@example.com> wrote:

On Fri, 26 Mar 2004 17:30:17 -0500, Chuck Harris <cfharris@erols.com
wrote:
[snip]

Ho hum, not what I would call much of a contest of wits ;-)

-Chuck Harris

Your observation skills rival those of Win... it's a TL431, NOT a
zener. Pay attention to how it's connected. Sheeesh!

...Jim Thompson

480)460-2350 | |
| E-mail Address at Website Fax

480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

Throughout the history of this great country there have actually
been people of only two political persuasions: fighters and cowards.
WE MUST NOT LET THE LATTER PREVAIL IN THE NEXT ELECTION!

Winfield Hill · Mar 27, 2004

Jim Thompson wrote...

Maybe it's too subtle for you guys. Think TL431 connected normally,
but cathode protected against high voltage with a cascode device.

Nope, we get it just fine (as you can tell by looking at my versions
of TL431, LMV431 and LM385-adj designs, now and in the past). No,
the problem is not having everything in front of one while writing,
that is, no nice ASCII schematics to look at. < score! > :&gt

Thanks,
- Win

whill_at_picovolt-dot-com

Winfield Hill · Mar 27, 2004

Winfield Hill wrote...

Finally, mine can be programmed to 100V, simply by changing the
resistor ratio and using a common cheap TIP32C power transistor.
Try that with a wimply 2n4401. < score!

I can keep my comment about wimpy transistors, right? < score! >

Thanks,
- Win

whill_at_picovolt-dot-com

What's a Good Sub for a 45V Zener?

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