On Tue, 11 Dec 2018 01:58:49 -0000, Rod Speed wrote:



"Bruce Farquhar" wrote in message
news
On Mon, 10 Dec 2018 23:43:14 -0000, Rod Speed
wrote:



"Bruce Farquhar" wrote in message
news On Mon, 10 Dec 2018 20:30:34 -0000, Rod Speed
wrote:



"Bruce Farquhar" wrote in message
news On Mon, 10 Dec 2018 18:48:55 -0000, Tim J wrote:



"Tim Streater" wrote in message
.. .
In article , Bruce Farquhar
wrote:

On Mon, 10 Dec 2018 09:22:20 -0000, Tim Streater

wrote:

In article , Bruce Farquhar
wrote:

On Sun, 09 Dec 2018 21:40:03 -0000, Rod Speed

wrote:

Bruce Farquhar wrote

A thermocouple produces enough to power a spacecraft?!?

It isnt a single thermocouple, it's a thermopile.
https://en.wikipedia.org/wiki/Thermopile
https://en.wikipedia.org/wiki/Nuclear_power_in_space

Or just for some small electronics?

Not small at all.

Why are these not used on earth?

Probably not that cheap, once you've made the Pu-238.

Whatever happened to those AA nuclear batteries? I assume
they worked the same.

What on earth are you talking about?

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

Not wanting to read the entire article, apart from space are we using
any
now?

Don't think so.

And eeek! Pacemakers! Don't think I like that idea.

Might be preferable to repeated surgery to change the battery tho.

Can't they charge it magnetically like with electric toothbrushes?

They can now, but didn't then.

I'm sure people with pacemakers never recharge them?

Because the battery technology is much better now.

I was thinking of people I knew 30 years ago.

Or at least only every several years, so they can't be using that much
power.

Depends on how often it has to zap the heart.

Does it output a constant tick or does it only do something when it detects an abnormal heart rhythm?

Or have some kind of recharger like watches that use wrist movement (oo
er) to charge the battery?

Doesn't produce enough power for a pacemaker.
They need rather more power than a watch does.

But presumably you can put a much bigger generator inside a human body
than inside a watch.

Sure. But inside the chest doesn't move around as much as the
wrist. That's what determines what energy there is to harvest.

I guess they could run a wire along to your arm or something.

Anyway I'm not so sure you're right. If your walking around, your whole body moves. And in the chest they can have a much larger generator. Something inside a watch is miniscule compared to something in your torso which could presumably approach the size of a fist.