Very fast rise time generator...

[micky]

In alt.home.repair, on Sat, 18 Feb 2023 00:30:30 -0000, \"Commander
Kinsey\" <CK1@nospam.com> wrote:

On Wed, 15 Feb 2023 07:01:02 -0000, micky <NONONOmisc07@fmguy.com> wrote:

In alt.home.repair, on Wed, 15 Feb 2023 01:57:40 -0500, Clare Snyder
clare@snyder.on.ca> wrote:


Mine has no output jacks or cords. Just a small nice wooden cabinet
with no holes, no jacks, maybe one 12\" wire as a transmitting antenna (I
have to go look again. Not sure if there\'s a wire.)

Ok, that\'s way more sophisticated, and more modern.
I\'ve never seen one like that.


Maybe 14 or 16\" square and 5\" high.

It might be from the 30\'s after my mother got married in 1929.

input of the radio, which was actually the audio amplifier section.

The radio could have a switch to disable the radio section or not, in
which case you would have to \"tune out\" the stations.

I have been lucky enough that there was no strong station at the
frequency. I left a note inside so I or the next owner doesn\'t have to
hunt for it.

The transmitter should be tunable.

...
Many were not, short of trimming the length of the antenna!!

Would that change the frequency?!

I didn\'t read carefully. I thought he said trimming the capacitor
that\'s in one of the tuned circuits.

No, trimming the length of the antenna would likely just decrease
transmission range.

 

[Rod Speed]

On Thu, 23 Feb 2023 11:06:57 +1100, NY <me@privacy.net> wrote:

On 22/02/2023 23:42, Bob F wrote:
On 2/22/2023 3:13 PM, John Larkin wrote:
On Wed, 22 Feb 2023 23:35:23 +0100, Peeler <trolltrap@valid.invalid
wrote:

On Wed, 22 Feb 2023 13:35:59 -0800, John Larkin, another obviously
brain
dead, senile BIGMOUTH, blathered:


Seriously, a purr may be an echolocation frequency chirp.

Seriously, you MUST do something about this senility of yours! LOL

Never heard of chirps? It\'s a mathematical transform of an impulse,
but doesn\'t need the big peak power. Big radars do it so they don\'t
ionize the air near the antenna.

Most critters, humans included, use some form of echolocation.

Look it up. It\'s interesting.

Even blind people do it.

Presumably *especially* blind people, because without sight they need to
develop other ways of detecting the world around them. I\'ve seen videos
of blind people who can describe their surroundings (even places they\'ve
never been to before) almost as if they are seeing them.

Weird. I did realise that some can do surprisingly
well, but didnt realise that they could do that.

I\'ve never heard of a sighted person who has mastered chirping and
echo-location,

Me neither.

but then there\'s no point if there are easier ways of seeing what\'s
nearby.

 

[Rod Speed]

On Thu, 23 Feb 2023 11:35:29 +1100, John Larkin
<jlarkin@highlandsnipmetechnology.com> wrote:

On Thu, 23 Feb 2023 00:06:57 +0000, NY <me@privacy.net> wrote:

On 22/02/2023 23:42, Bob F wrote:
On 2/22/2023 3:13 PM, John Larkin wrote:
On Wed, 22 Feb 2023 23:35:23 +0100, Peeler <trolltrap@valid.invalid
wrote:

On Wed, 22 Feb 2023 13:35:59 -0800, John Larkin, another obviously
brain
dead, senile BIGMOUTH, blathered:


Seriously, a purr may be an echolocation frequency chirp.

Seriously, you MUST do something about this senility of yours! LOL

Never heard of chirps? It\'s a mathematical transform of an impulse,
but doesn\'t need the big peak power. Big radars do it so they don\'t
ionize the air near the antenna.

Most critters, humans included, use some form of echolocation.

Look it up. It\'s interesting.


Even blind people do it.

Presumably *especially* blind people, because without sight they need to
develop other ways of detecting the world around them. I\'ve seen videos
of blind people who can describe their surroundings (even places they\'ve
never been to before) almost as if they are seeing them.

I\'ve never heard of a sighted person who has mastered chirping and
echo-location, but then there\'s no point if there are easier ways of
seeing what\'s nearby.

Humans can make pretty good clicks too. A click is good for
short-range location. I wonder if a cat can click.

Never noticed one doing anything like that.

The wiki article says that sighted people can learn to echolocate
pretty well.

https://en.wikipedia.org/wiki/Human_echolocation

 

[Dean Hoffman]

On Wednesday, February 15, 2023 at 1:25:46 PM UTC-6, Don Y wrote:

On 2/15/2023 12:18 PM, Dean Hoffman wrote:
On Wednesday, February 15, 2023 at 12:55:40 PM UTC-6, Don Y wrote:
On 2/15/2023 11:50 AM, Dean Hoffman wrote:
There are indoor motion detector light switches and lights.
You can also buy switches that you can remotely control.

I\'d lose the remote then find it in the last place I looked.
Clap On! Clap Off! ?

I had to look, of course. I remember seeing the commercials long ago thinking why would anyone want the Clap On Clap Off. Now I know. Ebay, Amazon, and Walmart all sell them.
By the way actress Raquel Welch just died at 82.

 

[Peeler]

On Sat, 18 Feb 2023 12:43:14 +1100, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

<FLUSH the abnormal trolling senile cretin\'s latest trollshit unread>

 

[Peeler]

\"Who or What is Rod Speed?

Rod Speed is an entirely modern phenomenon. Essentially, Rod Speed
is an insecure and worthless individual who has discovered he can
enhance his own self-esteem in his own eyes by playing \"the big, hard
man\" on the InterNet.\"

https://www.pcreview.co.uk/threads/rod-speed-faq.2973853/

--
The Natural Philosopher about senile Rodent:
\"Rod speed is not a Brexiteer. He is an Australian troll and arsehole.\"
Message-ID: <pu07vj$s5$2@dont-email.me>

 

[rbowman]

On Wed, 22 Feb 2023 10:42:21 -0500, Ed Pawlowski wrote:

I know someone that does just that. Some odd people calling for odd
things. Recent one was a woman calling from her apartment. This is at
4AM. \"There is a satellite dish on the roof and it is not needed.
Please send someone to take it down\"

https://www.washingtonpost.com/news/post-nation/wp/2018/04/19/911-
dispatcher-jailed-houston-woman-hung-up-on-thousands-of-callers/

 

[Martin Brown]

On 15/02/2023 18:21, Don Y wrote:

On 2/15/2023 9:24 AM, Martin Brown wrote:
On 15/02/2023 10:48, Mike Monett VE3BTI wrote:
Martin Brown <\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

The remaining big power hog is the garage lights.

Your fridge is a big power hog. Set the refrigerator temperature to the
highest setting, usually around 45 degrees F or 7 degrees C. This is an
excellent temperature for keeping vegetables, especially potatoes.

UK fridges are much less of a power hog than US ones. The power it
takes to keep cool depends mostly on how often it gets opened and how
full it is. 4C is a widely recognised safe temperature for storing
uncooked meat and fish much above that and you are asking for trouble.

I suspect (?) our frigs are larger than yours.  Ours is 23 cu ft
and that\'s the \"smaller\" variant of this model (the \"standard\"
is 28 cu ft).

*Much* larger! US fridges are often bigger than Dr Who\'s Tardis. A
friend has one more like a wardrobe than an fridge. I could hide in it!

A typical UK under counter kitchen fridge is about 100L capacity which I
think is about 4 cubic feet. Freezers do come in various larger sizes
but under the counter ones don\'t.

Replace filament bulbs with LEDs. The power savings is amazing. For
example,
a 100 W LED bulb only draws 12 watts. A 60 W LED bulb only draws 9
watts.

LED bulbs are a win but they have been a win for nearly a decade now.
I doubt if anyone has a significant number of filament bulbs in use
today. Even so the lighting circuits are trivial when compared to
cookers and water heaters (which is our single biggest heavy load if
the central heating isn\'t on).

A standard lighting circuit, here, is 15A (@120VAC).  Water heaters,
ovens/ranges, central air, etc. are all \"dedicated circuits\" in the
30A - 50A (@220VAC) range.  A (gas) furnace or refrigerator would
likely get a dedicated 15A (@120VAC) circuit, largely for reliability
(so nothing else sharing the circuit could compromise its availability)

Lighting circuits often address the lighting in multiple rooms on
a single circuit.  Ditto for general purpose \"receptacles\" in rooms
other than the kitchen.

Does the US have the same ring main configuration as the UK or is that
method peculiar to us? That is the room sockets form a continuous loop
with the cable going back to the mains distribution node. It has the
advantage of two paths back to the distribution board and so slightly
thinner wires for a given current carrying capacity (or lower losses).

It strikes me it would work even better on lower voltage higher current
US mains circuits if your wiring codes permit it.

--
Martin Brown

 

[Anthony Stewart]

On Saturday, February 11, 2023 at 3:16:52 a.m. UTC-5, Commander Kinsey wrote:
> Why do circuit breakers go up for on and down for off? Would they work installed upside down?

My breakers go left <> right. They are not affected by gravity.

Tony EE since 1975

 

[The Natural Philosopher]

On 17/02/2023 22:01, Carlos E.R. wrote:

On 2023-02-16 23:47, Commander Kinsey wrote:

I was interested in the charge state of a good battery, not if it was
fucked.

You need to read the charge in every cell. If the cell that happens to
have the balls say \"green\", 100 charged, but there is another cell with
no balls that says \"red\", 10% charge, and the other 4 cells you do not
know, but happen to be 80% charged, then the actual charge of the
battery is equal to the charge of the worst cell, ie, 10% (depending on
the intended usage).

However since a battery is an integrated single unit these days, who
cares what the individual cells are doing? One tests the whole battery
and replaces it as necessary.

The load testers test the battery by applying a small load to it ,
measuring the voltage drop, and inferring a voltage drop at the rated
Cold Cranking Amps.
That\'s all you need to do.


--
\"Women actually are capable of being far more than the feminists will
let them.\"

 

[SteveW]

On 15/02/2023 18:26, NY wrote:

On 15/02/2023 17:33, Max Demian wrote:
I think it was just chance, or perhaps a famous clock had hands moving
deiseil. (Adjacent cogs in a gear train move in opposite directions
and it just happened that the one with a twelve hour period was going
deiseil.) In any case, the first clocks with dials has the *dial*
rotating and the hand (with fingers I think) was stationary. No idea
which way they rotated.

That reminds me of some cars which have their speedos calibrated
clockwise but with 0 at the 2 o\'clock position and highest speed at
about the 10 o\'clock position, as opposed to 0 at 8 o\'clock and max
speed at 4 o\'clock. Takes a bit of getting used to.

Could be worse: they could have also calibrated it
anticlockwise=increase ;-)

I thing the AC Cobra used an anti-clockwise speedo.

 

[Max Demian]

On 17/02/2023 21:04, Commander Kinsey wrote:

On Wed, 15 Feb 2023 16:57:19 -0000, Max Demian <max_demian@bigfoot.com
wrote:
On 15/02/2023 14:48, Commander Kinsey wrote:

Mind you the whole idea of metal wheels on metal tracks is crazy.  If I
drive my car with bald tyres, I\'m breaking the law.

Works though; provided there are no \"leaves on the line\".

(Something to with the friction between similar metals I think.)

There\'s fuck all friction, which is why they want the cars to wait for
the train at a level crossing, and not the other way round.  And why the
new tunnel the Germans are building couldn\'t go right underground and
had to be installed on the bottom of the ocean, because the pathetic toy
trains couldn\'t handle the incline.  This is the 21st century, we have
cars.  Public transport is for chavs.

If there were no friction between train wheels and track acceleration
and braking wouldn\'t happen.

The reason railway tracks are so level is so that the engines can have
the minimum power to pull the train. Very steep inclines would require
extra locomotives to be put on to get up the hills.

--
Max Demian

 

[Vir Campestris]

On 16/02/2023 21:58, micky wrote:

Ah. A lof of safety enforcement is done by insurance companies that is
not covered by government regulation. Is that true in Spain and Europe
too?

That was our experience when we bought this house (UK) - they would only
give us temporary cover while we got it re-wired.

It was _legal_ to leave the old wiring there, but it wasn\'t safe.

Andy

 

[Clifford Heath]

On 16/02/23 04:33, ke...@kjwdesigns.com wrote:

The goal for this approach is 2kW average primary energy usage of all forms, ie 48kWh/day.

https://en.wikipedia.org/wiki/2000-watt_society

That makes a lot more sense. My quick calculation showed the global
average is around 1700W, so they\'re trying to bring the worst offenders
down to the average. That page says the USA is around 12kW, so there\'s
\"room for improvement\" as my primary school teacher used to say.

 

[Max Demian]

On 18/02/2023 00:29, Commander Kinsey wrote:

On Mon, 13 Feb 2023 13:58:47 -0000, micky <NONONOmisc07@fmguy.com> wrote:
In alt.home.repair, on Mon, 13 Feb 2023 13:33:36 +0000, Max Demian
max_demian@bigfoot.com> wrote:
On 13/02/2023 03:59, micky wrote:
In alt.home.repair, on Mon, 13 Feb 2023 00:08:57 +0100, \"Carlos E.R.\"
robin_listas@es.invalid> wrote:

Radios of that era had a setting named \"phone\". And a socket. You
connected the output of the \"electric gramophone\" pickup to the phone

Every mains valve radio had a \"Gram\" or \"PU\" socket with switching,
usually combined with the waveband switch.

Every AC tube radio....  

Mains was always AC wasn\'t it?

If course it wasn\'t (in the UK). Mains was AC or DC, and 120V (or so) to
250V (or so).

--
Max Demian

 

[Don Y]

On 2/15/2023 1:24 PM, Dean Hoffman wrote:

On Wednesday, February 15, 2023 at 1:25:46 PM UTC-6, Don Y wrote:
On 2/15/2023 12:18 PM, Dean Hoffman wrote:
On Wednesday, February 15, 2023 at 12:55:40 PM UTC-6, Don Y wrote:
On 2/15/2023 11:50 AM, Dean Hoffman wrote:
There are indoor motion detector light switches and lights.
You can also buy switches that you can remotely control.

I\'d lose the remote then find it in the last place I looked.
Clap On! Clap Off! ?

I had to look, of course. I remember seeing the commercials long ago
thinking why would anyone want the Clap On Clap Off. Now I know. Ebay,
Amazon, and Walmart all sell them.

I always thought it would be amusing to buy a pair of them
and connect a TV to each -- located within \"earshot\" of each
other. Turn (only) one on and wait for the commercial...

> By the way actress Raquel Welch just died at 82.

Gotta wonder how folks who base their existence on appearance
deal with the inevitability of aging. I saw Julie Newmar in a
show, some time ago. Definitely not what I\'d remembered... :<

 

[SteveW]

On 18/02/2023 12:43, Max Demian wrote:

On 18/02/2023 00:29, Commander Kinsey wrote:
On Mon, 13 Feb 2023 13:58:47 -0000, micky <NONONOmisc07@fmguy.com> wrote:
In alt.home.repair, on Mon, 13 Feb 2023 13:33:36 +0000, Max Demian
max_demian@bigfoot.com> wrote:
On 13/02/2023 03:59, micky wrote:
In alt.home.repair, on Mon, 13 Feb 2023 00:08:57 +0100, \"Carlos E.R.\"
robin_listas@es.invalid> wrote:

Radios of that era had a setting named \"phone\". And a socket. You
connected the output of the \"electric gramophone\" pickup to the phone

Every mains valve radio had a \"Gram\" or \"PU\" socket with switching,
usually combined with the waveband switch.

Every AC tube radio....  

Mains was always AC wasn\'t it?

If course it wasn\'t (in the UK). Mains was AC or DC, and 120V (or so) to
250V (or so).

Yes. Mains power was produced locally to each town or city. It was only
the building of the grid that standardised mains voltage and frequency
across the country.

 

[Klaus Vestergaard Kragelund]

On 15-02-2023 18:36, ke...@kjwdesigns.com wrote:

On Wednesday, 15 February 2023 at 07:17:57 UTC-8, Klaus Vestergaard Kragelund wrote:
On 15-02-2023 16:09, Jan Panteltje wrote:
On a sunny day (Wed, 15 Feb 2023 15:31:58 +0100) it happened Klaus Vestergaard
Kragelund <klau...@hotmail.com> wrote in <tsiqcv$2tidt$2...@dont-email.me>:

On 14-02-2023 22:54, Uwe Bonnes wrote:
John Larkin <jla...@highlandsnipmetechnology.com> wrote:

The diodes Inc/Zetex avalanche transistors are still available.

Higher rates are hard to reach with avalache transistors. What frequency
does the original poster need?

I can do with below 1MHz, just need the very high risetime

Relais contact?

30V - big cap - relais - your cap

It wont be that fast, from what I read wetted contacts can reach 10ns,
not in picoseconds

Mercury wetted relays can do picoseconds.

For example: https://fkh.ch/wp-content/uploads/2014/07/1999_Neuhold_Mercury-Switch-Pulse-Generator_High-Voltage-Engineering-Symposium.pdf

Nice, thanks for the link. That is a lot faster than I had seen before.
Repetition rate is not so good though, being mechanical function.

 

[John Miles, KE5FX]

On Tuesday, February 14, 2023 at 7:16:45 AM UTC-8, Klaus Kragelund wrote:
> Anyone got other ideas?

An amusing one to think about:

http://www.ke5fx.com/Nanoplasma_spark_gap_picosecond_switches_for_ultrafast_electronics.pdf

From my reply to an earlier (2020) thread where someone mentioned that paper:

--------snip--------
I tried cutting a slot in the top layer of a copper PCB strip using
a scalpel, the idea being to pinch it shut manually until it fires
somewhere near the bottom of the Paschen curve:

http://www.ke5fx.com/microgap/gap.jpg (closeup)
http://www.ke5fx.com/microgap/10x.jpg (test setup for HV edge)
http://www.ke5fx.com/microgap/50R.jpg (test setup for 50 ohms)

Driving it at -350V through a 100K resistor makes the gap fire somewhat
randomly at about 100 V/ns, limited by the probe and various strays.
The recovery time is also swamped by the scope probe RC:

http://www.ke5fx.com/microgap/mso_10x_probe_1us_div.png
http://www.ke5fx.com/microgap/mso_10x_probe_1ns_div.png

A 50-ohm series tap is faster, but likely still limited by strays:

http://www.ke5fx.com/microgap/mso_50R_1ns_div.png (MSO6054A, 500 MHz BW)
http://www.ke5fx.com/microgap/tds_50R_1ns.gif (TDS 694C, 3000 MHz BW)

I did see some edges closer to .35/3000 = 117 ps, but 164 ps was the
fastest one that I saved before the PCB strip finally broke.
--------end snip--------

So there\'s your 30 volts, and then some, I guess. Good luck in the EMC lab...

-- john, KE5FX

 

[Jan Panteltje]

On a sunny day (Wed, 15 Feb 2023 16:17:49 +0100) it happened Klaus Vestergaard
Kragelund <klauskvik@hotmail.com> wrote in <tsit2u$2tr9b$4@dont-email.me>:

On 15-02-2023 16:09, Jan Panteltje wrote:
On a sunny day (Wed, 15 Feb 2023 15:31:58 +0100) it happened Klaus Vestergaard
Kragelund <klauskvik@hotmail.com> wrote in <tsiqcv$2tidt$2@dont-email.me>:

On 14-02-2023 22:54, Uwe Bonnes wrote:
John Larkin <jlarkin@highlandsnipmetechnology.com> wrote:

The diodes Inc/Zetex avalanche transistors are still available.

Higher rates are hard to reach with avalache transistors. What frequency
does the original poster need?

I can do with below 1MHz, just need the very high risetime

Relais contact?

30V - big cap - relais - your cap

It wont be that fast, from what I read wetted contacts can reach 10ns,
not in picoseconds

Sure, depends on relais I am sure, induction of contact springs, what not..
I have some fast 50 Ohm ones (came from supercooler filter in a cellphone tower)
https://imgbox.com/wyXgqxBh
Now using imgbox to show stuff here, panteltje.com is \'off\'.

I\'d like to test it but have no scope that fast
Those relais on the left are 2 way switches, good for some GHz