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LTspice: X-Axis Variable...

A

amdx

Guest
On 6/20/2020 9:54 AM, jraffayroux@gmail.com wrote:
Hey, thanks for the input!
Mikek

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W

whit3rd

Guest
On Friday, June 19, 2020 at 3:59:31 PM UTC-7, Commander Kinsey wrote:

>... I just want to know how close to the correct reading the readout is. Adding another digit doesn\'t improve anything if it\'s incorrect. And shooting all the bullets in one place doesn\'t help if they all miss.

Not true; sometimes a reading difference doesn\'t have to be greater than the calibration error,
it still tells you something. Accuracy is not the only merit of an instrument, sensitivity
and precision matter.

A completely uncalibrated item (like a level or plumb bob) has no \'digits\' at all,
but is completely helpful.
 
A

amdx

Guest
On 6/20/2020 9:54 AM, jraffayroux@gmail.com wrote:
Hey, thanks for the input!
Mikek

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P

Phil Allison

Guest
Commander Kinsey wrote:
--------------------------

I\'d need to contract OCD to understand that.
** Lemme tell ya - you\'re already there.



...... Phil
 
P

Phil Allison

Guest
Commander Kinsey wrote:
--------------------------

I\'d need to contract OCD to understand that.
** Lemme tell ya - you\'re already there.



...... Phil
 
P

Phil Allison

Guest
Commander Kinsey wrote:
--------------------------

I\'d need to contract OCD to understand that.
** Lemme tell ya - you\'re already there.



...... Phil
 
J

Jasen Betts

Guest
On 2018-08-10, amdx <nojunk@knology.net> wrote:
Just
trying to build a light weight Leaf Blower for the wife to clean the
garage once a week.

Is it reasonable/possible to build an 8 amp 20 V transformerless power
supply from a 120Vac line.
depends what you mean \"transformerless\"

I calculate about 180uf plus or minus depending on other components.
Maybe 9- 20uf caps in parallel?
You are nuts! using a capacitive dropper to make 8A is crazy. what is
your plan for reinforcing the insulation on the leaf blower? Is this
a plot to kill your wife?

I\'d like to build it into a leaf blower.
All plastic, absolutely no metal exposed.
That seems half safe so far.

I think I\'ve answered my question, I have 12, X rated caps in my junk
box, but they are only 1uf.
The cheapest 20uf I can find is $3, so $27 for 9 caps. Not reasonable.

Just had another thought, I could mount a power supply with
transformer on the wall and have a cord go to the leaf blower.
That seems more reasonable, regular iron transformers with large
rectifiers work well for powering DC motor loads. switching supplies
can work too, but they usually need a current limit so that they can
survive a stall, it may be possible to attach a switching supoply
directly to the blower.


I guessing you don\'t have an air compressor (the type used for air
tools, not a mere tyre pumper) in your garage.



--
Jasen.
 
J

Jasen Betts

Guest
On 2018-08-10, amdx <nojunk@knology.net> wrote:
Just
trying to build a light weight Leaf Blower for the wife to clean the
garage once a week.

Is it reasonable/possible to build an 8 amp 20 V transformerless power
supply from a 120Vac line.
depends what you mean \"transformerless\"

I calculate about 180uf plus or minus depending on other components.
Maybe 9- 20uf caps in parallel?
You are nuts! using a capacitive dropper to make 8A is crazy. what is
your plan for reinforcing the insulation on the leaf blower? Is this
a plot to kill your wife?

I\'d like to build it into a leaf blower.
All plastic, absolutely no metal exposed.
That seems half safe so far.

I think I\'ve answered my question, I have 12, X rated caps in my junk
box, but they are only 1uf.
The cheapest 20uf I can find is $3, so $27 for 9 caps. Not reasonable.

Just had another thought, I could mount a power supply with
transformer on the wall and have a cord go to the leaf blower.
That seems more reasonable, regular iron transformers with large
rectifiers work well for powering DC motor loads. switching supplies
can work too, but they usually need a current limit so that they can
survive a stall, it may be possible to attach a switching supoply
directly to the blower.


I guessing you don\'t have an air compressor (the type used for air
tools, not a mere tyre pumper) in your garage.



--
Jasen.
 
J

Jasen Betts

Guest
On 2018-08-10, amdx <nojunk@knology.net> wrote:
Just
trying to build a light weight Leaf Blower for the wife to clean the
garage once a week.

Is it reasonable/possible to build an 8 amp 20 V transformerless power
supply from a 120Vac line.
depends what you mean \"transformerless\"

I calculate about 180uf plus or minus depending on other components.
Maybe 9- 20uf caps in parallel?
You are nuts! using a capacitive dropper to make 8A is crazy. what is
your plan for reinforcing the insulation on the leaf blower? Is this
a plot to kill your wife?

I\'d like to build it into a leaf blower.
All plastic, absolutely no metal exposed.
That seems half safe so far.

I think I\'ve answered my question, I have 12, X rated caps in my junk
box, but they are only 1uf.
The cheapest 20uf I can find is $3, so $27 for 9 caps. Not reasonable.

Just had another thought, I could mount a power supply with
transformer on the wall and have a cord go to the leaf blower.
That seems more reasonable, regular iron transformers with large
rectifiers work well for powering DC motor loads. switching supplies
can work too, but they usually need a current limit so that they can
survive a stall, it may be possible to attach a switching supoply
directly to the blower.


I guessing you don\'t have an air compressor (the type used for air
tools, not a mere tyre pumper) in your garage.



--
Jasen.
 
P

Phil Allison

Guest
amdx wrote:

-----------
Is it reasonable/possible to build an 8 amp 20 V transformerless power
supply from a 120Vac line.
I calculate about 180uf plus or minus depending on other components.
Maybe 9- 20uf caps in parallel?
I\'d like to build it into a leaf blower.
All plastic, absolutely no metal exposed.
** With a low resistance load, the inrush surge from a 180uF cap would trip the breaker.

SMPS have resistors or NTC thermistors in series with the AC supply stop this.

...... Phil
 
P

Phil Allison

Guest
amdx wrote:

-----------
Is it reasonable/possible to build an 8 amp 20 V transformerless power
supply from a 120Vac line.
I calculate about 180uf plus or minus depending on other components.
Maybe 9- 20uf caps in parallel?
I\'d like to build it into a leaf blower.
All plastic, absolutely no metal exposed.
** With a low resistance load, the inrush surge from a 180uF cap would trip the breaker.

SMPS have resistors or NTC thermistors in series with the AC supply stop this.

...... Phil
 
P

Phil Allison

Guest
amdx wrote:

-----------
Is it reasonable/possible to build an 8 amp 20 V transformerless power
supply from a 120Vac line.
I calculate about 180uf plus or minus depending on other components.
Maybe 9- 20uf caps in parallel?
I\'d like to build it into a leaf blower.
All plastic, absolutely no metal exposed.
** With a low resistance load, the inrush surge from a 180uF cap would trip the breaker.

SMPS have resistors or NTC thermistors in series with the AC supply stop this.

...... Phil
 
B

Bob Engelhardt

Guest
On 8/10/2018 1:24 PM, amdx wrote:
....
> Daughter gave me the leaf blower after the battery charger gave up.

Fix, build, or buy a battery charger.
 
B

Bob Engelhardt

Guest
On 8/10/2018 1:24 PM, amdx wrote:
....
> Daughter gave me the leaf blower after the battery charger gave up.

Fix, build, or buy a battery charger.
 
B

Bob Engelhardt

Guest
On 8/10/2018 1:24 PM, amdx wrote:
....
> Daughter gave me the leaf blower after the battery charger gave up.

Fix, build, or buy a battery charger.
 
A

amdx

Guest
On 6/21/2020 3:54 AM, Bob Engelhardt wrote:
On 8/10/2018 1:24 PM, amdx wrote:
...
Daughter gave me the leaf blower after the battery charger gave up.

Fix, build, or buy a battery charger.
And batteries, just not worth it.

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This email has been checked for viruses by Avast antivirus software.
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A

amdx

Guest
On 6/21/2020 3:54 AM, Bob Engelhardt wrote:
On 8/10/2018 1:24 PM, amdx wrote:
...
Daughter gave me the leaf blower after the battery charger gave up.

Fix, build, or buy a battery charger.
And batteries, just not worth it.

--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
 
A

amdx

Guest
On 6/21/2020 3:54 AM, Bob Engelhardt wrote:
On 8/10/2018 1:24 PM, amdx wrote:
...
Daughter gave me the leaf blower after the battery charger gave up.

Fix, build, or buy a battery charger.
And batteries, just not worth it.

--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
 
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