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Interesting Items...

Mike0001 said:
We used to pay a basic tax of 33%, now 20% seems too much for everyone, and we let the rich, the Sir Philips, Google, Apple, Amazon, pay no or very little tax.
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It's all part of the race to the bottom ... ie, which politician can offer voters all the goodies they want for no cost? For example, how was Labour's offer to scrap tuition fees anything but a bribe?
Unfortunately voters are a greedy and gullible bunch, and fall for it every time.
 
As also Bliar and Clegg, they both promised no increase in tuition fees, but trebled them. They also promised an interest free loan, but put the loan on a high interest rate, geared to the higher of two rates of inflation plus.

There were banks that gave investors a ridiculously high return once. Because of this, they suffered a run on their assets. The govt bailed them out, but the investors kept the high returns they had made.
 
Trev said:
It's the one growing in the bottom of my garden that JC wants to tax to the hilt.
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There is plenty that can be picked apart with respect to Labour's manifesto, but the so-called 'garden tax' was a fiction; an outright lie. Part of Lynton Crosby's grubby, underhand plan to crush Labour and give Terroresa May a large, undeserved, majority.
 
Fascinating! Here is more.

https://w2.eff.org/Privacy/printers/docucolor/

guide.png


  • 15: unknown (often zero; constant for each individual printer; may convey some non-user-visible fact about the printer's model or configuration)
  • 14, 13, 12, 11: printer serial number in binary-coded-decimal, two digits per byte (constant for each individual printer; see below)
  • 10: separator (typically all ones; does not appear to code information)
  • 9: unused
  • 8: year that page was printed (without century; 2005 is coded as 5)
  • 7: month that page was printed
  • 6: day that page was printed
  • 5: hour that page was printed (may be UTC time zone, or may be set inaccurately within printer)
  • 4, 3: unused
  • 2: minute that page was printed
  • 1: row parity bit (set to guarantee an odd number of dots present per row)
 
What with yellow dots on banknotes to try and stop you copying them, and now more yellow dots to identify which printer has printed them, they've really screwed up my latest money making idea. :(
 
We now know the cost of a life.

600 residents

£2 more per square metre for fire resistant cladding

2,000 square metres of cladding
 
I think that's about double the value. Last I read, the value of the materials of a decompiled human was about £3.50.
 
Yes, I have one like that (now pensioned off).

For anyone needing more explanation: a proper "universal" battery charger will monitor the voltage, current, and temperature for each cell being charged individually, and control the current being forced into it (which charges the cell) according to what the charger can deduce about the chemistry of the cell and its physical state, with regard given to best practice for each particular cell chemistry (normally NiCd or NiMH).

Simpler battery chargers will simply use a regulated current with a voltage cut-off, both values chosen to be safe (and therefore slower than can be done by a more intelligent process). This is the kind of thing illustrated in the preliminaries in the YouTube video.

Get this kind of thing wrong and there is risk of the cell shorting out internally and overheating as a result of rapid self-discharge, and/or gases being evolved which increase the internal pressure and either vent off or rupture (explode) the case. The gas is typically hydrogen so that implies a fire risk.

The charger in the video puts the cells more or less in parallel, each cell only separated from the others by a couple of resistors in parallel with LEDs. There is nothing to stop a cell overcharging (continuing to force current into it after it can't take any more). There is nothing to stop a faulty cell sorting out the others. It's the kind of thing that could result in a house fire if used unattended.

Lithium Ion cells are an entirely different matter - for one thing they have double the voltage so they need a charger capable of that higher voltage. They also have a much higher stored energy so are inherently more hazardous. Lithium itself is rather volatile and they need careful management (as is evident from Samsung's experience).
 
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Unless the batteries are to be charged at a very low currrent, they should be charged using a constant currant circuit, this is not present in the product being tested or the reviewers diagram, the item under most stress are the LEDS rather than the batteries, without constant current the batteries would take ages to charge fully, while the LEDS could have in excess of 150mA flowing through them at times
 
Ezra Pound said:
they should be charged using a constant current circuit
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Not necessarily, but relatively unsophisticated charging schemes tend to do so because the calculation of charge input (Coulombs) becomes proportional to the time it is applied for. Chargers that monitor the cell temperature reduce the input current if the temperature or voltage rises too quickly or exceeds a specified limit, whereas chargers that do not monitor the temperature may monitor the terminal voltage and reduce the current if the voltage rises too quickly, reducing the current as the voltage rises towards the limit voltage for the cell chemistry. Reconditioning chargers use pulsed current and may include periods of negative current (discharge).

Simple chargers settle for a current limited to an assumed safe charging current for all circumstances, but strictly speaking that is still not a "constant" current because it will be reduced as the cell climbs towards its voltage limit (and should be cut off when the voltage is reached).

Trickle chargers use a constant current, but at a greatly reduced value designed to be safe under all circumstances (including a fully charged cell), so are very slow to charge (rather than top up) a battery. These are mainly confined to lead-acid chemistries (eg car batteries), and are suitable for charging cells connected in series (other chemistries should not be charged while connected in series, unless at a trickle level).
 
BH : Simple chargers settle for a current limited to an assumed safe charging current for all circumstances, but strictly speaking that is still not a "constant"
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Current limiting is what we see in the crappy #1170 example and is OK. as long as a safe maximum current limit is selected, however it can't be used for 'fast' charging, constant current can be used for 'fast' charging if it is coupled with voltage monitoring to determine when charging should end
 
The crappiness of the example is that the cells are largely treated in parallel instead of being isolated from each other, from the power source, or with a limited voltage. Short out the input (ie turn off the power source) and the cells can drive back into the circuit; disconnect the input and the cells can drive each other (there's no guarantee the cells all have the same terminal voltage).

So the real issues are the lack of diodes, the lack of a series resistor per cell, and some form of cut-off when a voltage limit is reached. Given those, a limited current rather than a constant current would be adequate. Without those, only a trickle current would be satisfactory.
 
BH : Given those, a limited current rather than a constant current would be adequate.
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To charge the battery at an increasingly slow rate yes, a fixed resistance current limit that allows say 100mA to flow into a flat battery won't allow 100mA to flow into the same battery when partly charged, a constant current supply will
 
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