o*******g
发帖数: 1300 | |
o*******g
发帖数: 1300 | 2 用万用表测电阻应该是最保险的。
应该有个计算公式。
现在看来还是金币保险。 |
o*******g
发帖数: 1300 | 3
Resistivities at 20 °C
Material Resistivity (Ω•m)
Tungsten 5.60 × 10-8
5.60 × 10-8 Ωm
Material Resistivity (ohm-m)
Gold 2.44 × 10^-8
more than 100% difference.
Should be good to test raw bars. |
w*b
发帖数: 3001 | 4 这么大的家伙，俺们老百姓买不起。也就你海大人害怕进假货。 |
w*b
发帖数: 3001 | 5 据说那种超大的tungsten bar，会镀很厚的金子，有可能测不出来，必须打孔
【在 o*******g 的大作中提到】
:
: Resistivities at 20 °C
: Material Resistivity (Ω•m)
: Tungsten 5.60 × 10-8
: 5.60 × 10-8 Ωm
: Material Resistivity (ohm-m)
: Gold 2.44 × 10^-8
: more than 100% difference.
: Should be good to test raw bars.
|
j*******1
发帖数: 2045 | 6 买 1 oz 以下的应该还安全吧。作假的手工费要超过金子本身了。 |
e*****r
发帖数: 621 | 7 meaning even 1 oz gold coins can be suspicious? oh no... |
a*o
发帖数: 19981 | 8 10^-8 ..... 这个得搭桥测都未必准，而且这么粗的条那啥效应来着，电都从外面包的
金层走了，没准实测差别极小。打洞，唯有打洞。
【在 o*******g 的大作中提到】
:
: Resistivities at 20 °C
: Material Resistivity (Ω•m)
: Tungsten 5.60 × 10-8
: 5.60 × 10-8 Ωm
: Material Resistivity (ohm-m)
: Gold 2.44 × 10^-8
: more than 100% difference.
: Should be good to test raw bars.
|
a*o
发帖数: 19981 | 9 all had come from sources in the United States ... |
j*******1
发帖数: 2045 | 10 交流电集膚效应.You are correct, 打洞，唯有打洞。
【在 a*o 的大作中提到】
: 10^-8 ..... 这个得搭桥测都未必准，而且这么粗的条那啥效应来着，电都从外面包的
: 金层走了，没准实测差别极小。打洞，唯有打洞。
|
|
|
o*******g
发帖数: 1300 | 11 how about DC?
【在 j*******1 的大作中提到】
: 交流电集膚效应.You are correct, 打洞，唯有打洞。
|
j*******1
发帖数: 2045 | 12 gold Resistor's value = Resistivity*length/area
Even with DC, standard multimeter cannot read the gold bar's resistor value.The
resistor's value is too small, no matter it is T or G. Or maybe a highend multimeter can tell
If it is long thread, then standard multimeter may tell the differenc. |
j*******1
发帖数: 2045 | 13 try 比热容 or 热传导率 that will be easier to tell the difference between g and t |
w*b
发帖数: 3001 | 14 海大人用化骨棉掌来测最准。
g and t
【在 j*******1 的大作中提到】
: try 比热容 or 热传导率 that will be easier to tell the difference between g and t
|
a*o
发帖数: 19981 | 15 海大人一掌下去，金条没碎骨头碎了，海大人一声惨叫：啊～～～tungsten core！
【在 w*b 的大作中提到】
: 海大人用化骨棉掌来测最准。
:
: g and t
|
s*****j
发帖数: 4530 | 16 这玩意打了洞还值钱吗。。
剩下的金末子怎么办
【在 j*******1 的大作中提到】
: 交流电集膚效应.You are correct, 打洞，唯有打洞。
|
j*******1
发帖数: 2045 | 17 An easiest way is to drop it to hard ground. (don't drop it from too high
place, it will damage the bar). The tungsten is a very hard material, the
sound is different from real gold bar, which is very soft. Sound of gold is
very low like "pu1"
Buy a tungsten bar and do the same thing, you will know what I am talking
about....
I am just guessing... I did not try by myself. |
a*o
发帖数: 19981 | 18 晚上回家试试，我觉得够呛。
is
【在 j*******1 的大作中提到】
: An easiest way is to drop it to hard ground. (don't drop it from too high
: place, it will damage the bar). The tungsten is a very hard material, the
: sound is different from real gold bar, which is very soft. Sound of gold is
: very low like "pu1"
: Buy a tungsten bar and do the same thing, you will know what I am talking
: about....
: I am just guessing... I did not try by myself.
|
