DaveC wrote:
Panasonic 2.4v screwdriver battery pack consists of 2x sub-C cells in
series. Pack has (+) and (-) terminals, and a 3rd terminal (charge
sense?).

This 3rd terminal connects the charge circuit to the pack's (-)
terminal through 2 diodes and 2 resistors, all in series. The diodes
are glass with a yellow band. When I hook it up to the charger, the
diodes each drop 0.535v.

What are these diodes? Germanium would drop 0.3v or less, and silicon
would drop more than this 0.5, no?

They could be silicon. What was the current? A 1N4148 drops about 0.5v at
around 150 micro-amps.

Farnell sell Schottky diodes with forward voltage drops ranging from 0.2 to
1.2V.

"Andrew Holme" wrote in message
...
DaveC wrote:
Panasonic 2.4v screwdriver battery pack consists of 2x sub-C cells
in
series. Pack has (+) and (-) terminals, and a 3rd terminal (charge
sense?).

This 3rd terminal connects the charge circuit to the pack's (-)
terminal through 2 diodes and 2 resistors, all in series. The
diodes
are glass with a yellow band. When I hook it up to the charger,
the
diodes each drop 0.535v.

What are these diodes? Germanium would drop 0.3v or less, and
silicon
would drop more than this 0.5, no?

They could be silicon. What was the current? A 1N4148 drops about
0.5v at
around 150 micro-amps.

Farnell sell Schottky diodes with forward voltage drops ranging from
0.2 to
1.2V.




Actually a silicon diode drops 600mV, prettywell consistently
irrespective of type.

Have you tried reverse supply through a resistor? They could be
zeners.

Either way they are part of the charge sense or charging circuit. If
the battery has three contacts, then you have +ve out, -ve out, and
charge probably common to -ve. The diodes ensure polarity, the
resistors control the charge current, simple as that.


--
Woody

harrogate2 at ntlworld dot com

"DaveC" wrote in message
al.net...
Panasonic 2.4v screwdriver battery pack consists of 2x sub-C cells in
series.
Pack has (+) and (-) terminals, and a 3rd terminal (charge sense?).

This 3rd terminal connects the charge circuit to the pack's (-) terminal
through 2 diodes and 2 resistors, all in series. The diodes are glass with
a
yellow band. When I hook it up to the charger, the diodes each drop
0.535v.

What are these diodes? Germanium would drop 0.3v or less, and silicon
would
drop more than this 0.5, no?

I want to make more battery packs for this screwdriver and need to
identify
these diodes.


Most likely a 1N4148, a silicon diode. They are as common as muck and very
cheap.
http://www.semiconductors.philips.co...8_1N4448_5.pdf

You won't find germanium diodes in a battery pack, they're still used but
only for specialised purposes.

Dave

"harrogate2" wrote in message
...

"Andrew Holme" wrote in message
...
DaveC wrote:
Panasonic 2.4v screwdriver battery pack consists of 2x sub-C cells
in
series. Pack has (+) and (-) terminals, and a 3rd terminal (charge
sense?).

This 3rd terminal connects the charge circuit to the pack's (-)
terminal through 2 diodes and 2 resistors, all in series. The
diodes
are glass with a yellow band. When I hook it up to the charger,
the
diodes each drop 0.535v.

What are these diodes? Germanium would drop 0.3v or less, and
silicon
would drop more than this 0.5, no?

They could be silicon. What was the current? A 1N4148 drops about
0.5v at
around 150 micro-amps.

Farnell sell Schottky diodes with forward voltage drops ranging from
0.2 to
1.2V.




Actually a silicon diode drops 600mV, prettywell consistently
irrespective of type.


According to the datasheet, the 1N4148 drops 1V at 10mA, which surprised me.

Have you tried reverse supply through a resistor? They could be
zeners.

Either way they are part of the charge sense or charging circuit. If
the battery has three contacts, then you have +ve out, -ve out, and
charge probably common to -ve. The diodes ensure polarity, the
resistors control the charge current, simple as that.


Diodes can be used as temperature sensors, and there's an outside chance
that they monitor the battery temperature. It's unlikely but worth bearing
in mind.

If they are 1N4148s and they are carrying the charge current it seems a bit
of corner-cutting by the manufacturer. 1N400x would have been a better
option IMO.

Dave

"DaveC" wrote in message
al.net...
On Wed, 12 Jan 2005 12:46:42 -0800, harrogate2 wrote
(in article ):

Either way they are part of the charge sense or charging circuit. If
the battery has three contacts, then you have +ve out, -ve out, and
charge probably common to -ve. The diodes ensure polarity, the
resistors control the charge current, simple as that.

So the diode specs aren't really important (as long as they handle the
forward charge current, that is)?


Yes, if they are passing the charge current, but given the new info you've
provided, they aren't...

But why 2 diodes and 2 resistors, if the designers weren't trying to get
the
v. drop precise?

And why are there 2 resistors rather than 1 360-ohm one?
--

If the resistor really is 360 Ohms then the resistor and diode are not
passing the charge current, the resistor value is far too high for an approx
120mA charge current a standard C cell expects. Even with a 12V charger,
(very unlikely for a 2.4V battery pack) there would only be a 33mA charge
current through a 360Ohm resistor, which would take over 50 Hours to charge!

You'd need a 43V charger to give a 120mA charge current through a 360Ohm
resistor, and that's ignoring the drop across the NiCads and diodes.

The diodes and resistor have to be part of the sense circuit, so you'll need
to do a little digging into how the charger works.

Dave

"Dave D" wrote in message
...

"DaveC" wrote in message
But why 2 diodes and 2 resistors, if the designers weren't trying to get
the
v. drop precise?

And why are there 2 resistors rather than 1 360-ohm one?
--

The diodes and resistor have to be part of the sense circuit, so you'll
need
to do a little digging into how the charger works.

Could be a thermal resistor. That is, the charger senses when the battery
pack is getting too hot (due to charging) and shuts down the charger.

Jeff
--
Remove icky phrase from email address to get a valid address.

"Jeff Findley" wrote in message
...

"Dave D" wrote in message
...

"DaveC" wrote in message
But why 2 diodes and 2 resistors, if the designers weren't trying to
get
the
v. drop precise?

And why are there 2 resistors rather than 1 360-ohm one?
--

The diodes and resistor have to be part of the sense circuit, so you'll
need
to do a little digging into how the charger works.

Could be a thermal resistor. That is, the charger senses when the battery
pack is getting too hot (due to charging) and shuts down the charger.


Yes, I'm certainly inclined to think the devices are something to do with
temperature monitoring.

Dave

On Wed, 12 Jan 2005 11:21:08 -0800, DaveC wrote:

Panasonic 2.4v screwdriver battery pack consists of 2x sub-C cells in
series. Pack has (+) and (-) terminals, and a 3rd terminal (charge
sense?).

This 3rd terminal connects the charge circuit to the pack's (-) terminal
through 2 diodes and 2 resistors, all in series. The diodes are glass with
a yellow band. When I hook it up to the charger, the diodes each drop
0.535v.

What are these diodes? Germanium would drop 0.3v or less, and silicon
would drop more than this 0.5, no?

I want to make more battery packs for this screwdriver and need to
identify these diodes.

While they could be standard pn junction silicon diodes, my guess would be
they are schottky. TTYL

On Wed, 12 Jan 2005 20:46:42 +0000, harrogate2 wrote:


"Andrew Holme" wrote in message
...
DaveC wrote:
Panasonic 2.4v screwdriver battery pack consists of 2x sub-C cells
in
series. Pack has (+) and (-) terminals, and a 3rd terminal (charge
sense?).

This 3rd terminal connects the charge circuit to the pack's (-)
terminal through 2 diodes and 2 resistors, all in series. The
diodes
are glass with a yellow band. When I hook it up to the charger,
the
diodes each drop 0.535v.

What are these diodes? Germanium would drop 0.3v or less, and
silicon
would drop more than this 0.5, no?

They could be silicon. What was the current? A 1N4148 drops about
0.5v at
around 150 micro-amps.

Farnell sell Schottky diodes with forward voltage drops ranging from
0.2 to
1.2V.




Actually a silicon diode drops 600mV, prettywell consistently irrespective
of type.

No. The voltage drop of a diode is VERY dependant on the current flowing
through it, a 1N4001 diode can range in drop between ~0.3 and ~1.0
depending on the current flow. The 0.6 that is common is just a convinient
number to use. TTYL

"DaveC" wrote in message
al.net...
| On Wed, 12 Jan 2005 12:46:42 -0800, harrogate2 wrote
| (in article ):
|
| Either way they are part of the charge sense or charging circuit. If
| the battery has three contacts, then you have +ve out, -ve out, and
| charge probably common to -ve. The diodes ensure polarity, the
| resistors control the charge current, simple as that.
|
| So the diode specs aren't really important (as long as they handle the
| forward charge current, that is)?
|
| But why 2 diodes and 2 resistors, if the designers weren't trying to get
the
| v. drop precise?
|
| And why are there 2 resistors rather than 1 360-ohm one?

It's possibly how they tune the sense circuit to a particular battery pack.
Two resistors may be more flexible.

N

repatch wrote:
On Wed, 12 Jan 2005 11:21:08 -0800, DaveC wrote:


Panasonic 2.4v screwdriver battery pack consists of 2x sub-C cells in
series. Pack has (+) and (-) terminals, and a 3rd terminal (charge
sense?).

This 3rd terminal connects the charge circuit to the pack's (-) terminal
through 2 diodes and 2 resistors, all in series. The diodes are glass with
a yellow band. When I hook it up to the charger, the diodes each drop
0.535v.

What are these diodes? Germanium would drop 0.3v or less, and silicon
would drop more than this 0.5, no?

I want to make more battery packs for this screwdriver and need to
identify these diodes.


While they could be standard pn junction silicon diodes, my guess would be
they are schottky. TTYL


Why?

--
Return address is VALID.
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Bunch of stuff For Sale and Wanted at the link below.
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"DaveC" wrote in message
al.net...
Panasonic 2.4v screwdriver battery pack consists of 2x sub-C cells in
series.
Pack has (+) and (-) terminals, and a 3rd terminal (charge sense?).

This 3rd terminal connects the charge circuit to the pack's (-) terminal
through 2 diodes and 2 resistors, all in series. The diodes are glass with
a
yellow band. When I hook it up to the charger, the diodes each drop
0.535v.

What are these diodes? Germanium would drop 0.3v or less, and silicon
would
drop more than this 0.5, no?

I want to make more battery packs for this screwdriver and need to
identify
these diodes.

Thanks,
--
Please, no "Go Google this" replies. I wouldn't
ask a question here if I hadn't done that already.

DaveC

This is an invalid return address
Please reply in the news group

Does the third terminal connect to the junction of the two nicads? You can
check that by seeeing if it is at 1/2 voltage. Do the diodes make any
connection to that?

Tam

As others have pointed out, they could well be silicon diodes, but are they
temperature sensors? I'd expect to find temperature sensors in a battery
pack.

"DaveC" wrote in message
al.net...
Panasonic 2.4v screwdriver battery pack consists of 2x sub-C cells in
series.
Pack has (+) and (-) terminals, and a 3rd terminal (charge sense?).

This 3rd terminal connects the charge circuit to the pack's (-) terminal
through 2 diodes and 2 resistors, all in series. The diodes are glass with
a
yellow band. When I hook it up to the charger, the diodes each drop
0.535v.

What are these diodes? Germanium would drop 0.3v or less, and silicon
would
drop more than this 0.5, no?

I want to make more battery packs for this screwdriver and need to
identify
these diodes.

Thanks,
--
Please, no "Go Google this" replies. I wouldn't
ask a question here if I hadn't done that already.

DaveC

This is an invalid return address
Please reply in the news group

"mc" wrote in message
...
As others have pointed out, they could well be silicon diodes, but are
they
temperature sensors? I'd expect to find temperature sensors in a battery
pack.


They could be both. Diodes can be used to sense temperature.

Dave

On Wed, 12 Jan 2005 20:46:42 GMT, "harrogate2" wroth:



Actually a silicon diode drops 600mV, prettywell consistently
irrespective of type.


Actually, a silicon diode drops (in the forward direction) any value
from 0.0 volts to more than a volt depending on the current through it.

Take a look at some typical characteristic curves from the data sheets.

Jim

On Wed, 12 Jan 2005 23:41:14 +0000, Dave D wrote:


"mc" wrote in message
...
As others have pointed out, they could well be silicon diodes, but are
they
temperature sensors? I'd expect to find temperature sensors in a battery
pack.


They could be both. Diodes can be used to sense temperature.

If one is up against one cell, and the other is up against the other cell,
physically touching, then it's almost a sure thing that they're temp.
sensors.

Cheers!
Rich

On Wed, 12 Jan 2005 13:55:08 -0800, DaveC wrote:

On Wed, 12 Jan 2005 13:27:15 -0800, Dave D wrote
(in article ):

If the resistor really is 360 Ohms then the resistor and diode are not
passing the charge current,

The resistors and diodes are not in the path of the charge current. The (+)
and (-) cell terms are connected directly to the (+) and (-) terms of the
battery pack. The 3rd pack term connects to the (-) cell term via these
resistors and diodes.


It would have to be temperature sensing for charge termination purposes.

"DaveC" schreef in bericht
al.net...
Panasonic 2.4v screwdriver battery pack consists of 2x sub-C cells in
series.
Pack has (+) and (-) terminals, and a 3rd terminal (charge sense?).

This 3rd terminal connects the charge circuit to the pack's (-) terminal
through 2 diodes and 2 resistors, all in series. The diodes are glass with
a
yellow band. When I hook it up to the charger, the diodes each drop
0.535v.

What are these diodes? Germanium would drop 0.3v or less, and silicon
would
drop more than this 0.5, no?

I want to make more battery packs for this screwdriver and need to
identify
these diodes.

Thanks,
--
Please, no "Go Google this" replies. I wouldn't
ask a question here if I hadn't done that already.

DaveC

This is an invalid return address
Please reply in the news group


You did neither tell the resistor values nor the voltage measured across
them. Should be of some help. Can only guess these are old 1N914 or similar.
Most likely used for temperature sensing. The temperature itself is not very
important. It is the changing of it (dT/dt) that is used to decide whether
the batteries are fully charged.

petrus bitbyter

"DaveC" wrote in message
al.net...

| So, what diodes should I use if I want to duplicate the pack's circuitry?

Try a couple of 1N4001 and see how it works. You could try a trimmer in
place of the resistors and see how the charging is affected.

N

"DaveC" wrote in message
al.net...

| Sorry:
| Resistors: 240 ohm and 120 ohm.

Don't assume that they are just the nominal values. They may have been
selected.

N

"DaveC" wrote in message
al.net...

| Hmm... as in, depending on the vendor of the cells, the end-of-charge
| detection circuit needs to be tailor-made?

Not impossible. Cheaper than stocking a large number of precision resistors
with various values. There's no other good reason for two resistors, unless
this is a short production run.

N

On Wed, 12 Jan 2005 20:46:42 GMT "harrogate2"
wrote:

Actually a silicon diode drops 600mV, prettywell consistently
irrespective of type.

It IS independent of type, but it is completely dependent on current
and temp. If you check the data sheets, it varies from nearly zero
(for nearly zero current) to about 1V (at the device's full rated
current.) For typical current values, however, .5-.75V is a good
estimate.

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

Just to be different, Could the diodes and resistors be used to trickle
charge after the batteries are fully charged.
The charger output switches from the ( - ) neg of the battery to the
resistor diode string connected to ( - ) neg,
and allows for long times on the charger without cooking the batteries.
Mike

"DaveC" wrote in message
al.net...
Panasonic 2.4v screwdriver battery pack consists of 2x sub-C cells in
series.
Pack has (+) and (-) terminals, and a 3rd terminal (charge sense?).

This 3rd terminal connects the charge circuit to the pack's (-) terminal
through 2 diodes and 2 resistors, all in series. The diodes are glass with
a
yellow band. When I hook it up to the charger, the diodes each drop
0.535v.

What are these diodes? Germanium would drop 0.3v or less, and silicon
would
drop more than this 0.5, no?

I want to make more battery packs for this screwdriver and need to
identify
these diodes.

Thanks,
--
Please, no "Go Google this" replies. I wouldn't
ask a question here if I hadn't done that already.

DaveC

This is an invalid return address
Please reply in the news group

amdx wrote:

Just to be different, Could the diodes and resistors be used to trickle
charge after the batteries are fully charged.
The charger output switches from the ( - ) neg of the battery to the
resistor diode string connected to ( - ) neg,
and allows for long times on the charger without cooking the batteries.
Mike

Yet one more "different"... how about if the voltage drop
across the resistor is compared to the breakdown voltage
of the diode to determine the state of charge?

Ken

"amdx" wrote in message
...
| Just to be different, Could the diodes and resistors be used to trickle
| charge after the batteries are fully charged.
| The charger output switches from the ( - ) neg of the battery to the
| resistor diode string connected to ( - ) neg,
| and allows for long times on the charger without cooking the batteries.
| Mike

No point. Why put them in the battery? Makes more sense for either

1) Sensing

or

2) Calibrated compensation.

N

On Thu, 13 Jan 2005 04:51:15 GMT, "NSM" wrote:


"amdx" wrote in message
...
| Just to be different, Could the diodes and resistors be used to trickle
| charge after the batteries are fully charged.
| The charger output switches from the ( - ) neg of the battery to the
| resistor diode string connected to ( - ) neg,
| and allows for long times on the charger without cooking the batteries.
| Mike

No point. Why put them in the battery? Makes more sense for either

1) Sensing

or

2) Calibrated compensation.

N

Or it's there as a fuse.(thermally sensitive it blows when the battery
starts to overheat. Helps to prevent a battery exploding.)

On Wed, 12 Jan 2005 17:51:03 -0800, DaveC put finger
to keyboard and composed:

On Wed, 12 Jan 2005 17:31:01 -0800, petrus bitbyter wrote
(in article ):

You did neither tell the resistor values nor the voltage measured across
them. Should be of some help. Can only guess these are old 1N914 or similar.
Most likely used for temperature sensing. The temperature itself is not very
important. It is the changing of it (dT/dt) that is used to decide whether
the batteries are fully charged.

Sorry:
Resistors: 240 ohm and 120 ohm.

Pack is sealed up again. Forgot to measure. Sorry.

Does current flow into the third terminal or out of it, ie how are the
diodes oriented? Are the resistors really resistors? Do they have the
usual identifying bands? Does their resistnace change with
temperature? If you heat the components with a hair dryer during
charging, how does the charger respond? If you disconnect the third
terminal, what does the charger do? Is the charger designed to charge
battery packs of different voltages and, if so, do the resistors and
diodes somehow identify the number of cells???


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

Almost certain to be used as a temperature sensor (relying
on the "Diode Equation"), the abrupt rise in temperature
indicating when charging is complete.

"DaveC" wrote in message
al.net...
Panasonic 2.4v screwdriver battery pack consists of 2x sub-C cells in
series.
Pack has (+) and (-) terminals, and a 3rd terminal (charge sense?).

This 3rd terminal connects the charge circuit to the pack's (-) terminal
through 2 diodes and 2 resistors, all in series. The diodes are glass with
a
yellow band. When I hook it up to the charger, the diodes each drop
0.535v.

What are these diodes? Germanium would drop 0.3v or less, and silicon
would
drop more than this 0.5, no?

I want to make more battery packs for this screwdriver and need to
identify
these diodes.

Thanks,
--
Please, no "Go Google this" replies. I wouldn't
ask a question here if I hadn't done that already.

DaveC

This is an invalid return address
Please reply in the news group

These diodes are possibly needed to rectify the ac provided by the charging
transformer, so that the batteries recveive dc.Check with your multimeter if
the terminals of the charger supply ac.Usually the diodes are silicone, as
germanium is more expensive.Do you have a retailer of electronic gear in
vicinity that has experience in this kind of parts?The one I buy everything
can identify almost anything just with one look.

--
Tzortzakakis Dimitri?s
major in electrical engineering, freelance electrician
FH von Iraklion-Kreta, freiberuflicher Elektriker
dimtzort AT otenet DOT gr
? "DaveC" ?????? ??? ??????
al.net...
Panasonic 2.4v screwdriver battery pack consists of 2x sub-C cells in
series.
Pack has (+) and (-) terminals, and a 3rd terminal (charge sense?).

This 3rd terminal connects the charge circuit to the pack's (-) terminal
through 2 diodes and 2 resistors, all in series. The diodes are glass with
a
yellow band. When I hook it up to the charger, the diodes each drop
0.535v.

What are these diodes? Germanium would drop 0.3v or less, and silicon
would
drop more than this 0.5, no?

I want to make more battery packs for this screwdriver and need to
identify
these diodes.

Thanks,
--
Please, no "Go Google this" replies. I wouldn't
ask a question here if I hadn't done that already.

DaveC

This is an invalid return address
Please reply in the news group

There are 2 resistors rather than one of higher wattage.These were used
extenisevely withtube circuits (I mean high wattage resistors).
--
Tzortzakakis Dimitri?s
major in electrical engineering, freelance electrician
FH von Iraklion-Kreta, freiberuflicher Elektriker
dimtzort AT otenet DOT gr
? "DaveC" ?????? ??? ??????
al.net...
On Wed, 12 Jan 2005 12:46:42 -0800, harrogate2 wrote
(in article ):

Either way they are part of the charge sense or charging circuit. If
the battery has three contacts, then you have +ve out, -ve out, and
charge probably common to -ve. The diodes ensure polarity, the
resistors control the charge current, simple as that.

So the diode specs aren't really important (as long as they handle the
forward charge current, that is)?

But why 2 diodes and 2 resistors, if the designers weren't trying to get
the
v. drop precise?

And why are there 2 resistors rather than 1 360-ohm one?
--
Please, no "Go Google this" replies. I wouldn't
ask a question here if I hadn't done that already.

DaveC

This is an invalid return address
Please reply in the news group

On Wed, 12 Jan 2005 17:46:14 -0800, DaveC wrote:

On Wed, 12 Jan 2005 15:30:28 -0800, mc wrote (in article
):

As others have pointed out, they could well be silicon diodes, but are
they temperature sensors? I'd expect to find temperature sensors in a
battery pack.

They could be used as sensors, but they look just like common glass diodes
(1n4xxx type), to me.

However, while the diodes and resistors run alongside the cells, they are
(well, were) in shrink tubing and the cells are in a thick cardboard tube
(like a T.P. roll). Doesn't this make, logistically, for a poor temp
sensor location?

Depends on what you're sensing. For something like a NiCad sometimes you
can get away with just measuring the gradiant of the temp, for that the
setup you have is enough. TTYL

DaveC wrote:
Panasonic 2.4v screwdriver battery pack consists of 2x sub-C cells in series.
Pack has (+) and (-) terminals, and a 3rd terminal (charge sense?).

This 3rd terminal connects the charge circuit to the pack's (-) terminal
through 2 diodes and 2 resistors, all in series. The diodes are glass with a
yellow band. When I hook it up to the charger, the diodes each drop 0.535v.

What are these diodes? Germanium would drop 0.3v or less, and silicon would
drop more than this 0.5, no?

I want to make more battery packs for this screwdriver and need to identify
these diodes.

Thanks,

This has been another of those amusing threads.
You've gotten a zillion "answers" each of which could be paraphrased,
1)Stick your finger in the air, or your favorite orifice.
2)Make a GROSS, UNSUBSTANTIATED, SPECULATION based on NO, NONE, NOT ANY
information.

I read the thread again. I couldn't even find mention of the polarity
of the diodes in the circuit. Heck, one of us might even have relevant
information if only we knew the Panasonic model number.

You need to take apart the CHARGER and reverse engineer that.
If you published the schematic of the battery and charger, you MIGHT,
maybe, get a useful bit of information buried in the inevitable noise.
Then your problem would be reduced to deciding which of the conflicting
opinions to choose.

IF the charge termination is indeed based on temperature, and IF the
unknown elements are involved in temperature sensing, you need to
GET IT RIGHT. Did I mention IF???

Nah, who am I kidding. I'm certain the diodes are not diodes at all.
They're put there just to add to confusion in internet newsgroups.
Leave them out. Bummer, I think I got something on my finger... ;-)
mike

--
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Bunch of stuff For Sale and Wanted at the link below.
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"DaveC" wrote in message
al.net...
On Wed, 12 Jan 2005 17:30:21 -0800, budgie wrote
(in article ):

It would have to be temperature sensing for charge termination purposes.

So, what diodes should I use if I want to duplicate the pack's circuitry?

The first thing I'd do is take measurements at different temperatures so you
can characterize what's happening with the original.

Jeff
--
Remove icky phrase from email address to get a valid address.

Ah you're over here too..

The circuit in the pack is designed to match the charger.
If you can measure the forward voltage under a known current, and match that
to some common diode, then you're ok. They probably used cheap diodes, try
1n4001's and see where that gets you. Measure the voltage across the
resistors when it's in use, and that will tell you what test current to set
up.

"mike" wrote in message
...

| Nah, who am I kidding. I'm certain the diodes are not diodes at all.
| They're put there just to add to confusion in internet newsgroups.
| Leave them out. Bummer, I think I got something on my finger... ;-)

Actually, you're right. They're extra parts from the flying saucer used by
Kang and Kodos. They were going to build a rectal probe for Homer J, but, as
explained in "Treehouse of Horror VII" (1996) - The Halloween episode, they
decided against it. "I suppose you want to probe me," says Homer on board
the flying saucer and dropping his pants. "Well, you might as well get it
over with."

Kang replies, raising a tentacle, and shuddering: "Stop! We have reached the
limit of what rectal probing can teach us!"

I suspect we have reached the limit on what speculation on this battery can
teach us!

GW

(Always laugh at that one)

On Thu, 13 Jan 2005 16:52:42 +0200, "Dimitrios Tzortzakakis"
put finger to keyboard and composed:

There are 2 resistors rather than one of higher wattage.These were used
extenisevely withtube circuits (I mean high wattage resistors).

That doesn't explain why the two resistors aren't identical. I would
think that 2 x 180 makes more sense than 120 + 240. Could they be NTC
resistors?


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

"Franc Zabkar" wrote in message
...

| That doesn't explain why the two resistors aren't identical. I would
| think that 2 x 180 makes more sense than 120 + 240. Could they be NTC
| resistors?

Because they are hand picked 5% resistors, matched to the battery pack.

N

"NSM" wrote in message
news:K6BFd.99767$KO5.99427@clgrps13...

"Franc Zabkar" wrote in message
...

| That doesn't explain why the two resistors aren't identical. I would
| think that 2 x 180 makes more sense than 120 + 240. Could they be NTC
| resistors?

Because they are hand picked 5% resistors, matched to the battery pack.


The price difference between 5% &1% resistors in production volumes is zero.
The cost of 'hand picked 5% resistors to match the battery pack' - whatever
the latter means- is astronomic even in India or China.

"R.Lewis" wrote in message
...

| The price difference between 5% &1% resistors in production volumes is
zero.
| The cost of 'hand picked 5% resistors to match the battery pack' -
whatever
| the latter means- is astronomic even in India or China.

I've worked in production. Using two resistors in series is a dead give away
that they are tweaking the system. The other way is to use a 10 turn
trimmer. They didn't.

N

On Thu, 13 Jan 2005 23:29:53 GMT, "NSM" put finger to
keyboard and composed:


"R.Lewis" wrote in message
...

| The price difference between 5% &1% resistors in production volumes is
zero.
| The cost of 'hand picked 5% resistors to match the battery pack' -
whatever
| the latter means- is astronomic even in India or China.

I've worked in production. Using two resistors in series is a dead give away
that they are tweaking the system. The other way is to use a 10 turn
trimmer. They didn't.

N

I've encountered a Sansui amp where the main bridge rectifier was
constructed using four parallel pairs of 1A rectifier diodes rather
than four individual 2A or 3A diodes. Placing diodes in parallel is
bad practice because their sharp I-V characteristic almost guarantees
that one will work harder then the other, so my only conclusion is
that the manufacturer wanted to save money by making use of an
existing stock of 1N4004s. Maybe that's what happened in this case???


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.