On 22 Feb 2004 03:07:07 -0800, (Svante)
wrote:


The 500mA fuse in my experiment had a resistance of about 0.9 ohms
just before melting. The resistance increases with temperature. If the
thread is of silver, the resistance should increase by a factor 4 just
before melting, based on the melting point of silver. The resistance
measured with a multimeter was 0.2-0.3 ohms (when the fuse was cold).
A resistance of 0.9 ohms could have *some* audible effect IMO, so in
some sense resistance is a (small) issue.

---
Why do you think the fusible material is silver?

--
John Fields

John Fields wrote in message . ..
On 22 Feb 2004 03:07:07 -0800, (Svante)
wrote:


The 500mA fuse in my experiment had a resistance of about 0.9 ohms
just before melting. The resistance increases with temperature. If the
thread is of silver, the resistance should increase by a factor 4 just
before melting, based on the melting point of silver. The resistance
measured with a multimeter was 0.2-0.3 ohms (when the fuse was cold).
A resistance of 0.9 ohms could have *some* audible effect IMO, so in
some sense resistance is a (small) issue.

---
Why do you think the fusible material is silver?

Erhh... I don't know. I've always thought it was. What is it?

John Fields wrote in message . ..
On 22 Feb 2004 03:07:07 -0800, (Svante)
wrote:


The 500mA fuse in my experiment had a resistance of about 0.9 ohms
just before melting. The resistance increases with temperature. If the
thread is of silver, the resistance should increase by a factor 4 just
before melting, based on the melting point of silver. The resistance
measured with a multimeter was 0.2-0.3 ohms (when the fuse was cold).
A resistance of 0.9 ohms could have *some* audible effect IMO, so in
some sense resistance is a (small) issue.

---
Why do you think the fusible material is silver?

Erhh... I don't know. I've always thought it was. What is it?

John Fields wrote in message . ..
On 22 Feb 2004 03:07:07 -0800, (Svante)
wrote:


The 500mA fuse in my experiment had a resistance of about 0.9 ohms
just before melting. The resistance increases with temperature. If the
thread is of silver, the resistance should increase by a factor 4 just
before melting, based on the melting point of silver. The resistance
measured with a multimeter was 0.2-0.3 ohms (when the fuse was cold).
A resistance of 0.9 ohms could have *some* audible effect IMO, so in
some sense resistance is a (small) issue.

---
Why do you think the fusible material is silver?

Erhh... I don't know. I've always thought it was. What is it?

John Fields wrote in message . ..
On 22 Feb 2004 03:07:07 -0800, (Svante)
wrote:


The 500mA fuse in my experiment had a resistance of about 0.9 ohms
just before melting. The resistance increases with temperature. If the
thread is of silver, the resistance should increase by a factor 4 just
before melting, based on the melting point of silver. The resistance
measured with a multimeter was 0.2-0.3 ohms (when the fuse was cold).
A resistance of 0.9 ohms could have *some* audible effect IMO, so in
some sense resistance is a (small) issue.

---
Why do you think the fusible material is silver?

Erhh... I don't know. I've always thought it was. What is it?

Svante:
It is more like lead or tin or a combination of low melt point metals.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


"Svante" wrote in message
Why do you think the fusible material is silver?

Erhh... I don't know. I've always thought it was. What is it?

Svante:
It is more like lead or tin or a combination of low melt point metals.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


"Svante" wrote in message
Why do you think the fusible material is silver?

Erhh... I don't know. I've always thought it was. What is it?

Svante:
It is more like lead or tin or a combination of low melt point metals.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


"Svante" wrote in message
Why do you think the fusible material is silver?

Erhh... I don't know. I've always thought it was. What is it?

Svante:
It is more like lead or tin or a combination of low melt point metals.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


"Svante" wrote in message
Why do you think the fusible material is silver?

Erhh... I don't know. I've always thought it was. What is it?

On 23 Feb 2004 12:47:52 -0800, (Svante)
wrote:

John Fields wrote in message . ..
On 22 Feb 2004 03:07:07 -0800, (Svante)
wrote:


The 500mA fuse in my experiment had a resistance of about 0.9 ohms
just before melting. The resistance increases with temperature. If the
thread is of silver, the resistance should increase by a factor 4 just
before melting, based on the melting point of silver. The resistance
measured with a multimeter was 0.2-0.3 ohms (when the fuse was cold).
A resistance of 0.9 ohms could have *some* audible effect IMO, so in
some sense resistance is a (small) issue.

---
Why do you think the fusible material is silver?

Erhh... I don't know. I've always thought it was. What is it?

---
A zinc alloy, according to

http://www.littelfuse.com/PDFs/TechBriefs/TB98-004.pdf

but it seems to refer to their fuses with ribbon (instead of wire)
elements.

Just to check it out, if we look at silver with a melting point of 962°C
and an alpha (temperature coefficient of resistance) of 0.003819, we can
calculate the resistance at the melting point with


Rt = Rref ( 1 + (alpha (t - tref)))

Where
Rt is the resistance at the target temperature, in ohms
Rref is the resistance at the reference temperature (ambient), in ohms
alpha is 0.003819
t is the target temperature in degrees Celsius
tref is the reference temperature in degrees Celsius


If we split the difference between your 0.2-0.3 ohm cold resistance, we
get:

Rt = 0.25 ( 1 + (0.003819 (962 - 20))) ~ 1.5 ohms

which is quite a bit higher than your reported 0.9 ohms.



If we look at zinc, with a melting point of about 420°C and an alpha of
0.003847, we get:

Rt = 0.25 ( 1 + (0.003847 (420 - 20))) ~ 0.63 ohms

which is quite a bit lower, but since your fuse hadn't quite melted,
maybe in the ball park? Plus, they say it's a zinc _alloy_ ...

--
John Fields

On 23 Feb 2004 12:47:52 -0800, (Svante)
wrote:

John Fields wrote in message . ..
On 22 Feb 2004 03:07:07 -0800, (Svante)
wrote:


The 500mA fuse in my experiment had a resistance of about 0.9 ohms
just before melting. The resistance increases with temperature. If the
thread is of silver, the resistance should increase by a factor 4 just
before melting, based on the melting point of silver. The resistance
measured with a multimeter was 0.2-0.3 ohms (when the fuse was cold).
A resistance of 0.9 ohms could have *some* audible effect IMO, so in
some sense resistance is a (small) issue.

---
Why do you think the fusible material is silver?

Erhh... I don't know. I've always thought it was. What is it?

---
A zinc alloy, according to

http://www.littelfuse.com/PDFs/TechBriefs/TB98-004.pdf

but it seems to refer to their fuses with ribbon (instead of wire)
elements.

Just to check it out, if we look at silver with a melting point of 962°C
and an alpha (temperature coefficient of resistance) of 0.003819, we can
calculate the resistance at the melting point with


Rt = Rref ( 1 + (alpha (t - tref)))

Where
Rt is the resistance at the target temperature, in ohms
Rref is the resistance at the reference temperature (ambient), in ohms
alpha is 0.003819
t is the target temperature in degrees Celsius
tref is the reference temperature in degrees Celsius


If we split the difference between your 0.2-0.3 ohm cold resistance, we
get:

Rt = 0.25 ( 1 + (0.003819 (962 - 20))) ~ 1.5 ohms

which is quite a bit higher than your reported 0.9 ohms.



If we look at zinc, with a melting point of about 420°C and an alpha of
0.003847, we get:

Rt = 0.25 ( 1 + (0.003847 (420 - 20))) ~ 0.63 ohms

which is quite a bit lower, but since your fuse hadn't quite melted,
maybe in the ball park? Plus, they say it's a zinc _alloy_ ...

--
John Fields

On 23 Feb 2004 12:47:52 -0800, (Svante)
wrote:

John Fields wrote in message . ..
On 22 Feb 2004 03:07:07 -0800, (Svante)
wrote:


The 500mA fuse in my experiment had a resistance of about 0.9 ohms
just before melting. The resistance increases with temperature. If the
thread is of silver, the resistance should increase by a factor 4 just
before melting, based on the melting point of silver. The resistance
measured with a multimeter was 0.2-0.3 ohms (when the fuse was cold).
A resistance of 0.9 ohms could have *some* audible effect IMO, so in
some sense resistance is a (small) issue.

---
Why do you think the fusible material is silver?

Erhh... I don't know. I've always thought it was. What is it?

---
A zinc alloy, according to

http://www.littelfuse.com/PDFs/TechBriefs/TB98-004.pdf

but it seems to refer to their fuses with ribbon (instead of wire)
elements.

Just to check it out, if we look at silver with a melting point of 962°C
and an alpha (temperature coefficient of resistance) of 0.003819, we can
calculate the resistance at the melting point with


Rt = Rref ( 1 + (alpha (t - tref)))

Where
Rt is the resistance at the target temperature, in ohms
Rref is the resistance at the reference temperature (ambient), in ohms
alpha is 0.003819
t is the target temperature in degrees Celsius
tref is the reference temperature in degrees Celsius


If we split the difference between your 0.2-0.3 ohm cold resistance, we
get:

Rt = 0.25 ( 1 + (0.003819 (962 - 20))) ~ 1.5 ohms

which is quite a bit higher than your reported 0.9 ohms.



If we look at zinc, with a melting point of about 420°C and an alpha of
0.003847, we get:

Rt = 0.25 ( 1 + (0.003847 (420 - 20))) ~ 0.63 ohms

which is quite a bit lower, but since your fuse hadn't quite melted,
maybe in the ball park? Plus, they say it's a zinc _alloy_ ...

--
John Fields

On 23 Feb 2004 12:47:52 -0800, (Svante)
wrote:

John Fields wrote in message . ..
On 22 Feb 2004 03:07:07 -0800, (Svante)
wrote:


The 500mA fuse in my experiment had a resistance of about 0.9 ohms
just before melting. The resistance increases with temperature. If the
thread is of silver, the resistance should increase by a factor 4 just
before melting, based on the melting point of silver. The resistance
measured with a multimeter was 0.2-0.3 ohms (when the fuse was cold).
A resistance of 0.9 ohms could have *some* audible effect IMO, so in
some sense resistance is a (small) issue.

---
Why do you think the fusible material is silver?

Erhh... I don't know. I've always thought it was. What is it?

---
A zinc alloy, according to

http://www.littelfuse.com/PDFs/TechBriefs/TB98-004.pdf

but it seems to refer to their fuses with ribbon (instead of wire)
elements.

Just to check it out, if we look at silver with a melting point of 962°C
and an alpha (temperature coefficient of resistance) of 0.003819, we can
calculate the resistance at the melting point with


Rt = Rref ( 1 + (alpha (t - tref)))

Where
Rt is the resistance at the target temperature, in ohms
Rref is the resistance at the reference temperature (ambient), in ohms
alpha is 0.003819
t is the target temperature in degrees Celsius
tref is the reference temperature in degrees Celsius


If we split the difference between your 0.2-0.3 ohm cold resistance, we
get:

Rt = 0.25 ( 1 + (0.003819 (962 - 20))) ~ 1.5 ohms

which is quite a bit higher than your reported 0.9 ohms.



If we look at zinc, with a melting point of about 420°C and an alpha of
0.003847, we get:

Rt = 0.25 ( 1 + (0.003847 (420 - 20))) ~ 0.63 ohms

which is quite a bit lower, but since your fuse hadn't quite melted,
maybe in the ball park? Plus, they say it's a zinc _alloy_ ...

--
John Fields

"Sofie" wrote in message ...
Svante:
It is more like lead or tin or a combination of low melt point metals.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


"Svante" wrote in message
Why do you think the fusible material is silver?

Erhh... I don't know. I've always thought it was. What is it?

Interesting... Then I wonder why I saw an increase to 0.9 ohms before
melting (incresed from 0.2-0.3 ohms). This would indicate a melting
point of some 600-1100 degrees celcius. I'll have to up look tin/lead
alloys.

"Sofie" wrote in message ...
Svante:
It is more like lead or tin or a combination of low melt point metals.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


"Svante" wrote in message
Why do you think the fusible material is silver?

Erhh... I don't know. I've always thought it was. What is it?

Interesting... Then I wonder why I saw an increase to 0.9 ohms before
melting (incresed from 0.2-0.3 ohms). This would indicate a melting
point of some 600-1100 degrees celcius. I'll have to up look tin/lead
alloys.

"Sofie" wrote in message ...
Svante:
It is more like lead or tin or a combination of low melt point metals.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


"Svante" wrote in message
Why do you think the fusible material is silver?

Erhh... I don't know. I've always thought it was. What is it?

Interesting... Then I wonder why I saw an increase to 0.9 ohms before
melting (incresed from 0.2-0.3 ohms). This would indicate a melting
point of some 600-1100 degrees celcius. I'll have to up look tin/lead
alloys.

"Sofie" wrote in message ...
Svante:
It is more like lead or tin or a combination of low melt point metals.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


"Svante" wrote in message
Why do you think the fusible material is silver?

Erhh... I don't know. I've always thought it was. What is it?

Interesting... Then I wonder why I saw an increase to 0.9 ohms before
melting (incresed from 0.2-0.3 ohms). This would indicate a melting
point of some 600-1100 degrees celcius. I'll have to up look tin/lead
alloys.