1.5 VDC Pseudocell...

[Robert Roland]

On Sun, 08 Nov 2020 14:56:12 -0800, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>Or, buy one that does exactly what you\'re suggesting:

Sure, but you\'re taking all the fun out of it.
--
RoRo

 

[Don]

In sci.electronics.design Robert Roland <fake@ddress.no> wrote:

On Sun, 08 Nov 2020 14:56:12 -0800, Jeff Liebermann <jeffl@cruzio.com
wrote:

Or, buy one that does exactly what you\'re suggesting:

Sure, but you\'re taking all the fun out of it.

There\'s a few problems with the suggested off-the-shelf solution. [1]

The most project fun happened last, after piglet (and another at
eevblog) suggested 120R for R1 and 24R for R2. (piglet, with my last
sentence, it suddenly became obvious to me why you use R to denote ohms.
LOL.)
Although 120R and 24R certainly work, you may still ask, \"Are they
optimal?\" ROTFL. Let\'s have some fun and see!
First, you set up a system of simultaneous linear equations (details
shown at my updated link: https://crcomp.net/pseudocell/index.php ):

R1 R2

1 -5 0
1 1 150

Then you \"plug and chug\" the system through octave:

octave:1> A = [ 1 -5;

1 1 ]
A =

1 -5
1 1

octave:2> b = [ 0;

150 ]
b =

0
150

octave:3> r = A\\b
r =

125
25

Close enough for government work, no? Now, was that fun or what?

Note.

[1] First, there\'s no nearby electrical outlet to plug it into. Second,
it requires a larger, even more unsightly, hole in the wall, to
accommodate either a wall wart or pseudocell. The attic\'s unheated
and must be sealed afterward, so the project then creeps into
spackle and paint matching.

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.

 

[piglet]

On 09/11/2020 3:35 pm, Steve Wilson wrote:

piglet <erichpwagner@hotmail.com> wrote:

On 09/11/2020 2:06 pm, Don wrote:
In sci.electronics.design piglet <erichpwagner@hotmail.com> wrote:
On 08/11/2020 9:08 pm, Don wrote:
This project shows how to build a 1.5 VDC pseudocell to take the
place of an AA sized battery. The mechanical aspect of this project
offers the greatest challenge. The electronic portion utilizes an
easy to use LM317 adjustable voltage regulator to convert a 5 VDC
source to 1.5 VDC.

(excerpt)

https://crcomp.net/pseudocell/index.php

(Thank you In Advance to readers who alert me to typos and
whatnot.)

Danke,


Your circuit design description states that R3 provides the minimum
10mA load current. Yet the value of R3 is 15k which only draws 0.1mA
which when added to the R1/R2 divider current of 1.13mA means the
minimum load on the LM317 is only 1.2mA far short of the stated 10mA

You don\'t even need R3 - just change R1 to 120R and R2 to 24R.

Excellent! (As always, BTW.)
Looks like my worst fear was realized as sloppy discipline
allowed
a decimal point to slip down from mils to micros. Your hint about how
to eliminate R3 is much appreciated too.
My approach to technology previously untapped by me is to
approach
it with caution. And a R2 of hundreds of ohms somehow seemed safe,
until you helped me see things clearly in my mind\'s eye.
Anyhow, the perfboard will be quickly rebuilt with correct
components. It\'s mounted on an easily accessed backboard and plugged
into a strip connected to the UPS used for the phone system. The last
bit doesn\'t matter much, given how a long pole will be used to
correct the clock\'s drift.

A long pole risks damaging the clock hands.

A WWVB clock will correct the drift and automatically switch for daylight
savings. Batteries can last 3 years.

Danke,


Thanks Don, you are very welcome.

piglet

Science teaches us to verify.

I like your sig. Much better than doubting.

Claude Bernard is an interesting figure and is held as the first
scientist.

Actually I think that title should go to Michael Faraday and others from
his era.

Quote

\"Michael Faraday (born Sept. 22, 1791) was a British physicist and
chemist who is best known for his discoveries of electromagnetic
induction and of the laws of electrolysis. His biggest breakthrough in
electricity was his invention of the electric motor.\"

https://www.thoughtco.com/michael-faraday-inventor-4059933

https://www.sciencehistory.org/historical-profile/michael-faraday

Tesla was credited with invention of the electric motor, but he was a
century too late.

+1 on Faraday. Had the great pleasure to visit the Royal Institution in
London where Faraday worked.

piglet

Science teaches us to verify.

 

[Robert Roland]

On Tue, 10 Nov 2020 05:11:39 -0000 (UTC), \"Don\" <g@crcomp.net> wrote:

it requires a larger, even more unsightly, hole in the wall, to
accommodate either a wall wart or pseudocell.

In a pinch, you could snip the wire and splice it after you put it
through the hole.
--
RoRo

 

[Don]

In sci.electronics.design Robert Roland <fake@ddress.no> wrote:

On Tue, 10 Nov 2020 05:11:39 -0000 (UTC), \"Don\" <g@crcomp.net> wrote:

it requires a larger, even more unsightly, hole in the wall, to
accommodate either a wall wart or pseudocell.

In a pinch, you could snip the wire and splice it after you put it
through the hole.

A larger hole must be drilled in order to push the off-the-shelf
solution\'s flexible cable through it. Stiff wire was pushed through,
instead of pulled through with a snake, to keep the hole as small as
possible.
The solution\'s cable length is also about 94 feet too short.
Perhaps you can spice it to the stiff wire. But it\'s difficult for me to
fully apprise the situation from an image. And unpleasant surprises,
after a sometimes long wait for arrival, are anthematic to me.
It\'s also difficult for me to pay $28.99 for parts freely available
in my bone pile.

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.