Nuclear battery

On 2019-08-22, Martin Brown <'''newspam'''@nezumi.demon.co.uk> wrote:
On 22/08/2019 09:58, Jasen Betts wrote:
On 2019-08-21, Martin Brown <'''newspam'''@nezumi.demon.co.uk> wrote:

The snag with 3Ms product was that most people didn't understand the
advantage of having an emergency torch you could find in pitch darkness.
Modern mains supplies are so reliable people have forgotten the dark!

Also people carry emergency light sources in their pockets. My cellphone
has an OLED display one one side and a high power LED on the other.

Indeed. Although before the invention of smartphones that wasn't the
case. 3M were very unlucky that power white LEDs came along soon after
their rather nicely engineered emergency dayglo torch was launched.

It was interesting to see people using them in anger during the recent
UK powercut when emergency lighting in some London tube stations failed
to work (probably due to cuts to non-essential maintenance budgets).

I am surprised that modern LED torches don't bridge their switch with a
10M resistor. It doesn't affect battery life significantly and it makes
the thing so much easier to find in total darkness.
Click to expand...

the good ones have a switching powersupply before the LED, but yeah
the cheapies that run form 4.5 or 6V could be modified to glow in the
dark. I have a bicycle light that operates from 6V and glows a little
when the soft power switch is off.




--
When I tried casting out nines I made a hash of it.
 
On Saturday, August 24, 2019 at 3:01:34 AM UTC-4, Jasen Betts wrote:
On 2019-08-22, Martin Brown <'''newspam'''@nezumi.demon.co.uk> wrote:
On 22/08/2019 09:58, Jasen Betts wrote:
On 2019-08-21, Martin Brown <'''newspam'''@nezumi.demon.co.uk> wrote:

The snag with 3Ms product was that most people didn't understand the
advantage of having an emergency torch you could find in pitch darkness.
Modern mains supplies are so reliable people have forgotten the dark!

Also people carry emergency light sources in their pockets. My cellphone
has an OLED display one one side and a high power LED on the other.

Indeed. Although before the invention of smartphones that wasn't the
case. 3M were very unlucky that power white LEDs came along soon after
their rather nicely engineered emergency dayglo torch was launched.

It was interesting to see people using them in anger during the recent
UK powercut when emergency lighting in some London tube stations failed
to work (probably due to cuts to non-essential maintenance budgets).

I am surprised that modern LED torches don't bridge their switch with a
10M resistor. It doesn't affect battery life significantly and it makes
the thing so much easier to find in total darkness.

the good ones have a switching powersupply before the LED, but yeah
the cheapies that run form 4.5 or 6V could be modified to glow in the
dark. I have a bicycle light that operates from 6V and glows a little
when the soft power switch is off.
Click to expand...

Why on earth would you add a switching power supply to drive a handful of uA into an LED? The switcher would use more power than the LED!

--

Rick C.

---+ Get 1,000 miles of free Supercharging
---+ Tesla referral code - https://ts.la/richard11209
 
On 2019-08-24, Rick C <gnuarm.deletethisbit@gmail.com> wrote:

I am surprised that modern LED torches don't bridge their switch with a
10M resistor. It doesn't affect battery life significantly and it makes
the thing so much easier to find in total darkness.

the good ones have a switching powersupply before the LED, but yeah
the cheapies that run form 4.5 or 6V could be modified to glow in the
dark. I have a bicycle light that operates from 6V and glows a little
when the soft power switch is off.

Why on earth would you add a switching power supply to drive a
handful of uA into an LED? The switcher would use more power than the
LED!
Click to expand...

The switcher is there to put hundereds of mA through the led from a
1.5V supply.

--
When I tried casting out nines I made a hash of it.
 
On 24/08/2019 08:22, Rick C wrote:
On Saturday, August 24, 2019 at 3:01:34 AM UTC-4, Jasen Betts wrote:
On 2019-08-22, Martin Brown <'''newspam'''@nezumi.demon.co.uk
wrote:
On 22/08/2019 09:58, Jasen Betts wrote:
On 2019-08-21, Martin Brown <'''newspam'''@nezumi.demon.co.uk
wrote:

The snag with 3Ms product was that most people didn't
understand the advantage of having an emergency torch you
could find in pitch darkness. Modern mains supplies are so
reliable people have forgotten the dark!

Also people carry emergency light sources in their pockets. My
cellphone has an OLED display one one side and a high power LED
on the other.

Indeed. Although before the invention of smartphones that wasn't
the case. 3M were very unlucky that power white LEDs came along
soon after their rather nicely engineered emergency dayglo torch
was launched.

It was interesting to see people using them in anger during the
recent UK powercut when emergency lighting in some London tube
stations failed to work (probably due to cuts to non-essential
maintenance budgets).

I am surprised that modern LED torches don't bridge their switch
with a 10M resistor. It doesn't affect battery life significantly
and it makes the thing so much easier to find in total darkness.

the good ones have a switching powersupply before the LED, but
yeah the cheapies that run form 4.5 or 6V could be modified to glow
in the dark. I have a bicycle light that operates from 6V and
glows a little when the soft power switch is off.

Why on earth would you add a switching power supply to drive a
handful of uA into an LED? The switcher would use more power than
the LED!
Click to expand...

Because typically an LED torch is ~0.3-1A constant current and using a
switched mode supply allows you to get away with a lighter torch.

--
Regards,
Martin Brown
 
On Saturday, August 24, 2019 at 12:53:06 PM UTC-4, k...@notreal.com wrote:
On Sat, 24 Aug 2019 13:47:21 +0100, Martin Brown
'''newspam'''@nezumi.demon.co.uk> wrote:

On 24/08/2019 08:22, Rick C wrote:
On Saturday, August 24, 2019 at 3:01:34 AM UTC-4, Jasen Betts wrote:
On 2019-08-22, Martin Brown <'''newspam'''@nezumi.demon.co.uk
wrote:
On 22/08/2019 09:58, Jasen Betts wrote:
On 2019-08-21, Martin Brown <'''newspam'''@nezumi.demon.co.uk
wrote:

The snag with 3Ms product was that most people didn't
understand the advantage of having an emergency torch you
could find in pitch darkness. Modern mains supplies are so
reliable people have forgotten the dark!

Also people carry emergency light sources in their pockets. My
cellphone has an OLED display one one side and a high power LED
on the other.

Indeed. Although before the invention of smartphones that wasn't
the case. 3M were very unlucky that power white LEDs came along
soon after their rather nicely engineered emergency dayglo torch
was launched.

It was interesting to see people using them in anger during the
recent UK powercut when emergency lighting in some London tube
stations failed to work (probably due to cuts to non-essential
maintenance budgets).

I am surprised that modern LED torches don't bridge their switch
with a 10M resistor. It doesn't affect battery life significantly
and it makes the thing so much easier to find in total darkness.

the good ones have a switching powersupply before the LED, but
yeah the cheapies that run form 4.5 or 6V could be modified to glow
in the dark. I have a bicycle light that operates from 6V and
glows a little when the soft power switch is off.

Why on earth would you add a switching power supply to drive a
handful of uA into an LED? The switcher would use more power than
the LED!

Because typically an LED torch is ~0.3-1A constant current and using a
switched mode supply allows you to get away with a lighter torch.

And more importantly, less wasted power. The switching supply can
supply the few microamps as a finder current, too. Low-Iq switchers
are all about, these days. If one doesn't like that idea, a large
resistor to supply the leakage, still works.
Click to expand...

Yep, a large resistor around the current regulator and switch. No point in screwing with inductors and switchers to save an additional 10 or 15%. An LED and current regulator are 73% efficient. The efficiency gets better as the battery voltage drops. By the time the voltage gets too low to work some 80 or 90% of the battery is used up.

Screwing with a switcher is just not worth the trouble. Heck, someone invented a very thin bracket to put around a AA battery to do the joule thief thing and it has a significant cost. My LED light only cost $10 and works great. Add a switcher and it would be $15.

--

Rick C.

--++ Get 1,000 miles of free Supercharging
--++ Tesla referral code - https://ts.la/richard11209
 
On Saturday, August 24, 2019 at 5:31:50 AM UTC-4, Jasen Betts wrote:
On 2019-08-24, Rick C <gnuarm.deletethisbit@gmail.com> wrote:

I am surprised that modern LED torches don't bridge their switch with a
10M resistor. It doesn't affect battery life significantly and it makes
the thing so much easier to find in total darkness.

the good ones have a switching powersupply before the LED, but yeah
the cheapies that run form 4.5 or 6V could be modified to glow in the
dark. I have a bicycle light that operates from 6V and glows a little
when the soft power switch is off.

Why on earth would you add a switching power supply to drive a
handful of uA into an LED? The switcher would use more power than the
LED!

The switcher is there to put hundereds of mA through the led from a
1.5V supply.
Click to expand...

That's not what you wrote about. If you analyze the actual efficiency of such circuits you will find the losses in a switcher are not much less than the losses in a linear running from 4.5 volts. Most LED lights uses 4.5 volts. I don't think the choice of going with a single 1.5 volt cell or 3 cells is an issue of "cheapies". It's just a design decision and the 3 cell units hold up longer because of the higher energy in three cells compared to one. Unless size/weight were an important factor, I'd go with the 3 cell solution.

--

Rick C.

--+- Get 1,000 miles of free Supercharging
--+- Tesla referral code - https://ts.la/richard11209
 
On Sat, 24 Aug 2019 13:47:21 +0100, Martin Brown
<'''newspam'''@nezumi.demon.co.uk> wrote:

On 24/08/2019 08:22, Rick C wrote:
On Saturday, August 24, 2019 at 3:01:34 AM UTC-4, Jasen Betts wrote:
On 2019-08-22, Martin Brown <'''newspam'''@nezumi.demon.co.uk
wrote:
On 22/08/2019 09:58, Jasen Betts wrote:
On 2019-08-21, Martin Brown <'''newspam'''@nezumi.demon.co.uk
wrote:

The snag with 3Ms product was that most people didn't
understand the advantage of having an emergency torch you
could find in pitch darkness. Modern mains supplies are so
reliable people have forgotten the dark!

Also people carry emergency light sources in their pockets. My
cellphone has an OLED display one one side and a high power LED
on the other.

Indeed. Although before the invention of smartphones that wasn't
the case. 3M were very unlucky that power white LEDs came along
soon after their rather nicely engineered emergency dayglo torch
was launched.

It was interesting to see people using them in anger during the
recent UK powercut when emergency lighting in some London tube
stations failed to work (probably due to cuts to non-essential
maintenance budgets).

I am surprised that modern LED torches don't bridge their switch
with a 10M resistor. It doesn't affect battery life significantly
and it makes the thing so much easier to find in total darkness.

the good ones have a switching powersupply before the LED, but
yeah the cheapies that run form 4.5 or 6V could be modified to glow
in the dark. I have a bicycle light that operates from 6V and
glows a little when the soft power switch is off.

Why on earth would you add a switching power supply to drive a
handful of uA into an LED? The switcher would use more power than
the LED!

Because typically an LED torch is ~0.3-1A constant current and using a
switched mode supply allows you to get away with a lighter torch.
Click to expand...

And more importantly, less wasted power. The switching supply can
supply the few microamps as a finder current, too. Low-Iq switchers
are all about, these days. If one doesn't like that idea, a large
resistor to supply the leakage, still works.
 
On Sat, 24 Aug 2019 10:22:30 -0700 (PDT), Rick C
<gnuarm.deletethisbit@gmail.com> wrote:

On Saturday, August 24, 2019 at 12:53:06 PM UTC-4, k...@notreal.com wrote:
On Sat, 24 Aug 2019 13:47:21 +0100, Martin Brown
'''newspam'''@nezumi.demon.co.uk> wrote:

On 24/08/2019 08:22, Rick C wrote:
On Saturday, August 24, 2019 at 3:01:34 AM UTC-4, Jasen Betts wrote:
On 2019-08-22, Martin Brown <'''newspam'''@nezumi.demon.co.uk
wrote:
On 22/08/2019 09:58, Jasen Betts wrote:
On 2019-08-21, Martin Brown <'''newspam'''@nezumi.demon.co.uk
wrote:

The snag with 3Ms product was that most people didn't
understand the advantage of having an emergency torch you
could find in pitch darkness. Modern mains supplies are so
reliable people have forgotten the dark!

Also people carry emergency light sources in their pockets. My
cellphone has an OLED display one one side and a high power LED
on the other.

Indeed. Although before the invention of smartphones that wasn't
the case. 3M were very unlucky that power white LEDs came along
soon after their rather nicely engineered emergency dayglo torch
was launched.

It was interesting to see people using them in anger during the
recent UK powercut when emergency lighting in some London tube
stations failed to work (probably due to cuts to non-essential
maintenance budgets).

I am surprised that modern LED torches don't bridge their switch
with a 10M resistor. It doesn't affect battery life significantly
and it makes the thing so much easier to find in total darkness.

the good ones have a switching powersupply before the LED, but
yeah the cheapies that run form 4.5 or 6V could be modified to glow
in the dark. I have a bicycle light that operates from 6V and
glows a little when the soft power switch is off.

Why on earth would you add a switching power supply to drive a
handful of uA into an LED? The switcher would use more power than
the LED!

Because typically an LED torch is ~0.3-1A constant current and using a
switched mode supply allows you to get away with a lighter torch.

And more importantly, less wasted power. The switching supply can
supply the few microamps as a finder current, too. Low-Iq switchers
are all about, these days. If one doesn't like that idea, a large
resistor to supply the leakage, still works.

Yep, a large resistor around the current regulator and switch. No point in screwing with inductors and switchers to save an additional 10 or 15%. An LED and current regulator are 73% efficient. The efficiency gets better as the battery voltage drops. By the time the voltage gets too low to work some 80 or 90% of the battery is used up.

Screwing with a switcher is just not worth the trouble. Heck, someone invented a very thin bracket to put around a AA battery to do the joule thief thing and it has a significant cost. My LED light only cost $10 and works great. Add a switcher and it would be $15.
Click to expand...

Utter nonsense.
 
On Saturday, August 24, 2019 at 9:32:03 PM UTC-4, k...@notreal.com wrote:
On Sat, 24 Aug 2019 10:22:30 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:

On Saturday, August 24, 2019 at 12:53:06 PM UTC-4, k...@notreal.com wrote:
On Sat, 24 Aug 2019 13:47:21 +0100, Martin Brown
'''newspam'''@nezumi.demon.co.uk> wrote:

On 24/08/2019 08:22, Rick C wrote:
On Saturday, August 24, 2019 at 3:01:34 AM UTC-4, Jasen Betts wrote:
On 2019-08-22, Martin Brown <'''newspam'''@nezumi.demon.co.uk
wrote:
On 22/08/2019 09:58, Jasen Betts wrote:
On 2019-08-21, Martin Brown <'''newspam'''@nezumi.demon.co.uk
wrote:

The snag with 3Ms product was that most people didn't
understand the advantage of having an emergency torch you
could find in pitch darkness. Modern mains supplies are so
reliable people have forgotten the dark!

Also people carry emergency light sources in their pockets. My
cellphone has an OLED display one one side and a high power LED
on the other.

Indeed. Although before the invention of smartphones that wasn't
the case. 3M were very unlucky that power white LEDs came along
soon after their rather nicely engineered emergency dayglo torch
was launched.

It was interesting to see people using them in anger during the
recent UK powercut when emergency lighting in some London tube
stations failed to work (probably due to cuts to non-essential
maintenance budgets).

I am surprised that modern LED torches don't bridge their switch
with a 10M resistor. It doesn't affect battery life significantly
and it makes the thing so much easier to find in total darkness.

the good ones have a switching powersupply before the LED, but
yeah the cheapies that run form 4.5 or 6V could be modified to glow
in the dark. I have a bicycle light that operates from 6V and
glows a little when the soft power switch is off.

Why on earth would you add a switching power supply to drive a
handful of uA into an LED? The switcher would use more power than
the LED!

Because typically an LED torch is ~0.3-1A constant current and using a
switched mode supply allows you to get away with a lighter torch.

And more importantly, less wasted power. The switching supply can
supply the few microamps as a finder current, too. Low-Iq switchers
are all about, these days. If one doesn't like that idea, a large
resistor to supply the leakage, still works.

Yep, a large resistor around the current regulator and switch. No point in screwing with inductors and switchers to save an additional 10 or 15%. An LED and current regulator are 73% efficient. The efficiency gets better as the battery voltage drops. By the time the voltage gets too low to work some 80 or 90% of the battery is used up.

Screwing with a switcher is just not worth the trouble. Heck, someone invented a very thin bracket to put around a AA battery to do the joule thief thing and it has a significant cost. My LED light only cost $10 and works great. Add a switcher and it would be $15.

Utter nonsense.
Click to expand...

Yes, using a switcher to get 10% better efficiency from a $0.25 battery is exactly that, utter nonsense.

--

Rick C.

--++ Get 1,000 miles of free Supercharging
--++ Tesla referral code - https://ts.la/richard11209
 
On Sat, 24 Aug 2019 18:45:28 -0700 (PDT), Rick C
<gnuarm.deletethisbit@gmail.com> wrote:

On Saturday, August 24, 2019 at 9:32:03 PM UTC-4, k...@notreal.com wrote:
On Sat, 24 Aug 2019 10:22:30 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:

On Saturday, August 24, 2019 at 12:53:06 PM UTC-4, k...@notreal.com wrote:
On Sat, 24 Aug 2019 13:47:21 +0100, Martin Brown
'''newspam'''@nezumi.demon.co.uk> wrote:

On 24/08/2019 08:22, Rick C wrote:
On Saturday, August 24, 2019 at 3:01:34 AM UTC-4, Jasen Betts wrote:
On 2019-08-22, Martin Brown <'''newspam'''@nezumi.demon.co.uk
wrote:
On 22/08/2019 09:58, Jasen Betts wrote:
On 2019-08-21, Martin Brown <'''newspam'''@nezumi.demon.co.uk
wrote:

The snag with 3Ms product was that most people didn't
understand the advantage of having an emergency torch you
could find in pitch darkness. Modern mains supplies are so
reliable people have forgotten the dark!

Also people carry emergency light sources in their pockets. My
cellphone has an OLED display one one side and a high power LED
on the other.

Indeed. Although before the invention of smartphones that wasn't
the case. 3M were very unlucky that power white LEDs came along
soon after their rather nicely engineered emergency dayglo torch
was launched.

It was interesting to see people using them in anger during the
recent UK powercut when emergency lighting in some London tube
stations failed to work (probably due to cuts to non-essential
maintenance budgets).

I am surprised that modern LED torches don't bridge their switch
with a 10M resistor. It doesn't affect battery life significantly
and it makes the thing so much easier to find in total darkness.

the good ones have a switching powersupply before the LED, but
yeah the cheapies that run form 4.5 or 6V could be modified to glow
in the dark. I have a bicycle light that operates from 6V and
glows a little when the soft power switch is off.

Why on earth would you add a switching power supply to drive a
handful of uA into an LED? The switcher would use more power than
the LED!

Because typically an LED torch is ~0.3-1A constant current and using a
switched mode supply allows you to get away with a lighter torch.

And more importantly, less wasted power. The switching supply can
supply the few microamps as a finder current, too. Low-Iq switchers
are all about, these days. If one doesn't like that idea, a large
resistor to supply the leakage, still works.

Yep, a large resistor around the current regulator and switch. No point in screwing with inductors and switchers to save an additional 10 or 15%. An LED and current regulator are 73% efficient. The efficiency gets better as the battery voltage drops. By the time the voltage gets too low to work some 80 or 90% of the battery is used up.

Screwing with a switcher is just not worth the trouble. Heck, someone invented a very thin bracket to put around a AA battery to do the joule thief thing and it has a significant cost. My LED light only cost $10 and works great. Add a switcher and it would be $15.

Utter nonsense.

Yes, using a switcher to get 10% better efficiency from a $0.25 battery is exactly that, utter nonsense.
Click to expand...

$5? Bullshit. You're completely full of shit, in fact.
 
On 25/08/2019 02:45, Rick C wrote:
On Saturday, August 24, 2019 at 9:32:03 PM UTC-4, k...@notreal.com
wrote:
On Sat, 24 Aug 2019 10:22:30 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:

On Saturday, August 24, 2019 at 12:53:06 PM UTC-4,
k...@notreal.com wrote:
On Sat, 24 Aug 2019 13:47:21 +0100, Martin Brown
'''newspam'''@nezumi.demon.co.uk> wrote:

Because typically an LED torch is ~0.3-1A constant current
and using a switched mode supply allows you to get away with
a lighter torch.

And more importantly, less wasted power. The switching supply
can supply the few microamps as a finder current, too. Low-Iq
switchers are all about, these days. If one doesn't like that
idea, a large resistor to supply the leakage, still works.
Click to expand...

I don't think they care so much about the linear wasted power but the
switched mode current source trick made single AA battery LED torches
possible for under $5. They even do flashing modes as well.

The big advantage is that the thing runs at almost constant brightness
right up until the battery is really on its last legs. This can be a
disadvantage I have had more than one Duracell corrode on me recently.
Other cheaper brands do not seem to fail so annoyingly. I don't know if
they are clever forgeries or what but I have stopped using them.

Yep, a large resistor around the current regulator and switch.
No point in screwing with inductors and switchers to save an
additional 10 or 15%. An LED and current regulator are 73%
efficient. The efficiency gets better as the battery voltage
drops. By the time the voltage gets too low to work some 80 or
90% of the battery is used up.

Screwing with a switcher is just not worth the trouble. Heck,
someone invented a very thin bracket to put around a AA battery
to do the joule thief thing and it has a significant cost. My
LED light only cost $10 and works great. Add a switcher and it
would be $15.

Utter nonsense.

Yes, using a switcher to get 10% better efficiency from a $0.25
battery is exactly that, utter nonsense.
Click to expand...

There are chips that can do it for next to nothing and have been for
some while. I recall a low power sample device being a give away on the
front of a popular electronics magazine back in the early 2000's.

--
Regards,
Martin Brown
 
lørdag den 24. august 2019 kl. 19.22.35 UTC+2 skrev Rick C:
On Saturday, August 24, 2019 at 12:53:06 PM UTC-4, k...@notreal.com wrote:
On Sat, 24 Aug 2019 13:47:21 +0100, Martin Brown
'''newspam'''@nezumi.demon.co.uk> wrote:

On 24/08/2019 08:22, Rick C wrote:
On Saturday, August 24, 2019 at 3:01:34 AM UTC-4, Jasen Betts wrote:
On 2019-08-22, Martin Brown <'''newspam'''@nezumi.demon.co.uk
wrote:
On 22/08/2019 09:58, Jasen Betts wrote:
On 2019-08-21, Martin Brown <'''newspam'''@nezumi.demon.co.uk
wrote:

The snag with 3Ms product was that most people didn't
understand the advantage of having an emergency torch you
could find in pitch darkness. Modern mains supplies are so
reliable people have forgotten the dark!

Also people carry emergency light sources in their pockets. My
cellphone has an OLED display one one side and a high power LED
on the other.

Indeed. Although before the invention of smartphones that wasn't
the case. 3M were very unlucky that power white LEDs came along
soon after their rather nicely engineered emergency dayglo torch
was launched.

It was interesting to see people using them in anger during the
recent UK powercut when emergency lighting in some London tube
stations failed to work (probably due to cuts to non-essential
maintenance budgets).

I am surprised that modern LED torches don't bridge their switch
with a 10M resistor. It doesn't affect battery life significantly
and it makes the thing so much easier to find in total darkness.

the good ones have a switching powersupply before the LED, but
yeah the cheapies that run form 4.5 or 6V could be modified to glow
in the dark. I have a bicycle light that operates from 6V and
glows a little when the soft power switch is off.

Why on earth would you add a switching power supply to drive a
handful of uA into an LED? The switcher would use more power than
the LED!

Because typically an LED torch is ~0.3-1A constant current and using a
switched mode supply allows you to get away with a lighter torch.

And more importantly, less wasted power. The switching supply can
supply the few microamps as a finder current, too. Low-Iq switchers
are all about, these days. If one doesn't like that idea, a large
resistor to supply the leakage, still works.

Yep, a large resistor around the current regulator and switch. No point in screwing with inductors and switchers to save an additional 10 or 15%. An LED and current regulator are 73% efficient. The efficiency gets better as the battery voltage drops. By the time the voltage gets too low to work some 80 or 90% of the battery is used up.

Screwing with a switcher is just not worth the trouble. Heck, someone invented a very thin bracket to put around a AA battery to do the joule thief thing and it has a significant cost. My LED light only cost $10 and works great. Add a switcher and it would be $15.
Click to expand...

https://lcsc.com/product-detail/LED-Drivers_QX-Micro-Devices-QX5252F_C236054.html
 
On Sunday, August 25, 2019 at 4:48:57 AM UTC-4, Martin Brown wrote:
On 25/08/2019 02:45, Rick C wrote:
On Saturday, August 24, 2019 at 9:32:03 PM UTC-4, k...@notreal.com
wrote:
On Sat, 24 Aug 2019 10:22:30 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:

On Saturday, August 24, 2019 at 12:53:06 PM UTC-4,
k...@notreal.com wrote:
On Sat, 24 Aug 2019 13:47:21 +0100, Martin Brown
'''newspam'''@nezumi.demon.co.uk> wrote:

Because typically an LED torch is ~0.3-1A constant current
and using a switched mode supply allows you to get away with
a lighter torch.

And more importantly, less wasted power. The switching supply
can supply the few microamps as a finder current, too. Low-Iq
switchers are all about, these days. If one doesn't like that
idea, a large resistor to supply the leakage, still works.

I don't think they care so much about the linear wasted power but the
switched mode current source trick made single AA battery LED torches
possible for under $5. They even do flashing modes as well.

The big advantage is that the thing runs at almost constant brightness
right up until the battery is really on its last legs. This can be a
disadvantage I have had more than one Duracell corrode on me recently.
Other cheaper brands do not seem to fail so annoyingly. I don't know if
they are clever forgeries or what but I have stopped using them.

Yep, a large resistor around the current regulator and switch.
No point in screwing with inductors and switchers to save an
additional 10 or 15%. An LED and current regulator are 73%
efficient. The efficiency gets better as the battery voltage
drops. By the time the voltage gets too low to work some 80 or
90% of the battery is used up.

Screwing with a switcher is just not worth the trouble. Heck,
someone invented a very thin bracket to put around a AA battery
to do the joule thief thing and it has a significant cost. My
LED light only cost $10 and works great. Add a switcher and it
would be $15.

Utter nonsense.

Yes, using a switcher to get 10% better efficiency from a $0.25
battery is exactly that, utter nonsense.

There are chips that can do it for next to nothing and have been for
some while. I recall a low power sample device being a give away on the
front of a popular electronics magazine back in the early 2000's.
Click to expand...

The fact that something is given away doesn't make it cheap. Tesla "gave" me free Supercharging worth $30,000 or more.

The chip is about the same cost as the inductor. The point is it provides virtually no benefit (personally I see the blinking mode as a liability) if the buyer doesn't know it's there.

Sans the inductor a simple current source chip or circuit (how many transistors? 2, 1?) Is cheaper and very effective.

--

Rick C.

-+-- Get 1,000 miles of free Supercharging
-+-- Tesla referral code - https://ts.la/richard11209
 
On Wednesday, August 21, 2019 at 8:07:44 AM UTC-7, jla...@highlandsniptechnology.com wrote:

I took a good green LED up to the cabin where it's really dark at
night. I got up at 2AM and ran a little test. The threshold of
visibility was about 1 nA. I didn't expect that an LED would emit any
photons at 1 nA, much less that I could see them.

Maybe I'll try that again, with the super-good Osrams of various
colors. The blue is blinding at 5 mA, even though human vision peaks
in the green.
Click to expand...

But you get good power efficiency from red, and green is the peak for NIGHT
vision, which means one is light-blind the moment you switch it off.
Red light doesn't desensitize the low-light (rod) cells, so a red illuminator
doesn't leave you blind in the moonlight afterward.

An old-fashioned solution is a neon lamp in a light switch (I'm using one for the
garage, and another for the hallway), and the newer one is an outlet-plate that
steals AC for low-level lighting

<https://www.amazon.com/night-light-cover-plate/s?k=night+light+cover+plate>

but neither does much for the 'find my flashlight' problem when power is out.
 
Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> wrote:

John Doe wrote:
Piotr Wyderski <peter.pan@neverland.mil> wrote:

Not terribly innovative on its own, but given the DIY aspect and
price, it can be a viable "eternal" auxiliary power supply for
some hi-rel devices:

In case anybody doesn't already know... NASA depends on nuclear
batteries for its deep space probes.

Not a battery, but a reactor, a big block of radioactive stuff,
surrounded by
a few thousand thermocouples.
The heat from the core is converted to electricity.
Click to expand...

Thanks. How is the original subject fundamentally different?

> So, a generator instead of a battery.

I wouldn't call the gasoline motor in a generator a "generator". And in
fact, NASA calls them "batteries". Others call them "batteries", like
folks at Stanford university...

"Review and Preview of Nuclear Battery Technology"
http://large.stanford.edu/courses/2017/ph241/park-j1/
 
John Doe <always.look@message.header> wrote:

Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> wrote:
John Doe wrote:
Piotr Wyderski <peter.pan@neverland.mil> wrote:

Not terribly innovative on its own, but given the DIY aspect
and price, it can be a viable "eternal" auxiliary power supply
for some hi-rel devices:

In case anybody doesn't already know... NASA depends on nuclear
batteries for its deep space probes.

Not a battery, but a reactor, a big block of radioactive stuff,
surrounded by a few thousand thermocouples. The heat from the
core is converted to electricity.

Thanks. How is the original subject fundamentally different?

So, a generator instead of a battery.

I wouldn't call the gasoline motor in a generator a "generator".
And in fact, NASA calls them "batteries". Others call them
"batteries", like folks at Stanford university...

"Review and Preview of Nuclear Battery Technology"
http://large.stanford.edu/courses/2017/ph241/park-j1/
Click to expand...

According to that article, it's fundamentally no different than the
original subject. See the chapter "Betavoltaic Cells".

The nuclear battery technology Radioactive Thermoelectric Generator
(RTG) NASA uses is just one of many possible uses for nuclear
batteries.

A nuclear battery is not a conventional battery, but we can refer to
it as a battery.
 
On Sunday, August 25, 2019 at 1:44:42 PM UTC-4, whit3rd wrote:
An old-fashioned solution is a neon lamp in a light switch (I'm using one for the
garage, and another for the hallway), and the newer one is an outlet-plate that
steals AC for low-level lighting

https://www.amazon.com/night-light-cover-plate/s?k=night+light+cover+plate

but neither does much for the 'find my flashlight' problem when power is out.
Click to expand...

I bought a couple of LED recessed fixtures and a couple of dimmer switches that the LED figure recommended for compatibility. The dimmers had a light (likely a neon bulb) across the switch. The LEDs act as a nightlight because of the current through the neon bulbs. lol The dimmer switches control the LED erratically and the initial half of the dimmer switch movement does nothing.

I'd hate to see how badly a non-recommended dimmer would work.

--

Rick C.

-+-+ Get 1,000 miles of free Supercharging
-+-+ Tesla referral code - https://ts.la/richard11209
 
If not for USENET, where would trolls like this hang out...

--
Rick C <gnuarm.deletethisbit gmail.com> wrote:

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Subject: Re: Nuclear battery
From: Rick C <gnuarm.deletethisbit gmail.com
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Xref: reader01.eternal-september.org sci.electronics.design:562785

On Monday, August 26, 2019 at 12:00:44 AM UTC-4, John Doe wrote:
Sjouke Burry <burrynulnulfour ppllaanneett.nnll> wrote:

John Doe wrote:
Piotr Wyderski <peter.pan neverland.mil> wrote:

Not terribly innovative on its own, but given the DIY aspect and
price, it can be a viable "eternal" auxiliary power supply for
some hi-rel devices:

In case anybody doesn't already know... NASA depends on nuclear
batteries for its deep space probes.

Not a battery, but a reactor, a big block of radioactive stuff,
surrounded by
a few thousand thermocouples.
The heat from the core is converted to electricity.

Thanks. How is the original subject fundamentally different?

So, a generator instead of a battery.

I wouldn't call the gasoline motor in a generator a "generator". And in
fact, NASA calls them "batteries". Others call them "batteries", like
folks at Stanford university...

"Review and Preview of Nuclear Battery Technology"
http://large.stanford.edu/courses/2017/ph241/park-j1/

I guess a carbon-zinc cell is a primary chemical generator.

--

Rick C.

-++- Get 1,000 miles of free Supercharging
-++- Tesla referral code - https://ts.la/richard11209
Click to expand...
 
On Monday, August 26, 2019 at 4:16:44 PM UTC+10, John Doe wrote:
If not for USENET, where would trolls like this hang out...

--
Rick C <gnuarm.deletethisbit gmail.com> wrote:
Click to expand...

Since John Doe is the very definition of top-posting troll, almost unique in having nothing useful or entertaining to say, he does illustrate the problem.

Rick C may have his problems, but he isn't a troll. The fact that John Doe doesn't like him might be evidence in his favour, but John Doe is such total disaster that his opinions can only be discarded.

--
Bill Sloman, Sydney
 
On 25/08/2019 18:44, whit3rd wrote:
On Wednesday, August 21, 2019 at 8:07:44 AM UTC-7, jla...@highlandsniptechnology.com wrote:

I took a good green LED up to the cabin where it's really dark at
night. I got up at 2AM and ran a little test. The threshold of
visibility was about 1 nA. I didn't expect that an LED would emit any
photons at 1 nA, much less that I could see them.

Maybe I'll try that again, with the super-good Osrams of various
colors. The blue is blinding at 5 mA, even though human vision peaks
in the green.

But you get good power efficiency from red, and green is the peak for NIGHT
vision, which means one is light-blind the moment you switch it off.
Click to expand...

Scotopic vision at night peaks at around 510nm in the green which is the
rods peak sensitivity. That rod pigment is unaffected by red light
beyond 600nm so you can afford to use that without losing night vision.
Submarines and observatory control rooms used to be lit that way and
many still are. There has been a recent switch to very dim white light.

Red light doesn't desensitize the low-light (rod) cells, so a red illuminator
doesn't leave you blind in the moonlight afterward.
Click to expand...

Moonlight is *way* more than you need. The red light requirement is so
that you can still see the very faintest stars without having to wait
half an hour for the pigment to recover. Another interesting trick is to
breathe pure oxygen which boosts the eyes sensitivity (especially when
at high altitude which most professional observatories are).
An old-fashioned solution is a neon lamp in a light switch (I'm using one for the
garage, and another for the hallway), and the newer one is an outlet-plate that
steals AC for low-level lighting

https://www.amazon.com/night-light-cover-plate/s?k=night+light+cover+plate

but neither does much for the 'find my flashlight' problem when power is out.
Click to expand...

It is easy enough to make a red LED torch. It was pretty much the first
thing amateur astronomers did when the first red LEDs became available.
True long wave glass filters were expensive luxuries back then.

Interestingly though now when reading charts very dim white light
pointed downwards is preferred since many people find long wavelength
red light very hard to read by. Provided you keep it diffuse it doesn't
affect your night vision any more than looking at the milky way does.

--
Regards,
Martin Brown
 
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