J
JFS
Guest
Why 0.47uf or 47uf? Is there a significance to that value or is it just a
randomly chosen value?
randomly chosen value?
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M
Michael Black
Guest
JFS (none@none.com) writes:
I gather there was a time when there weren't such standard values. Or
maybe it was that they weren't placed at quite the best values.
So at one point, the "standard values" we know today came along. It
was something like with a given tolerance, and we're talking when 20%
tolerance was common, you didn't need values at every point on the scale,
but on the other hand, the tolerance set the stage for the next value up.
Add 20% to 47K and you get 56K and add 20% to that and you get just under
68K.
When higher tolerance resistors came along, of course they filled in some
of the blanks.
That's not an exact answer, but it goes something along those lines. It
was most definitely not a random choice.
Michael
There was, though I can't actually remember the reasoning.Why 0.47uf or 47uf? Is there a significance to that value or is it just a
randomly chosen value?
I gather there was a time when there weren't such standard values. Or
maybe it was that they weren't placed at quite the best values.
So at one point, the "standard values" we know today came along. It
was something like with a given tolerance, and we're talking when 20%
tolerance was common, you didn't need values at every point on the scale,
but on the other hand, the tolerance set the stage for the next value up.
Add 20% to 47K and you get 56K and add 20% to that and you get just under
68K.
When higher tolerance resistors came along, of course they filled in some
of the blanks.
That's not an exact answer, but it goes something along those lines. It
was most definitely not a random choice.
Michael
V
vic
Guest
JFS wrote:
as music notes frequencies. For example the E12 series has 12 different
values between each decade, the factor between successive values is
calculated like this :
k = 10^(1/12) = 1.2115
V1 = 10 and Vn = k*V(n-1)
Which gives the following values (rounded)
calculated values: 10, 12, 15, 18, 22, 26, 32, 38, 46, 56, 68, 83, 100
E12 values : 10, 12, 15, 18, 22, 27, 33, 38, 47, 56, 68, 83, 100
For some reason there are slight differences but it's very close.
You can notice that there is about 20% difference between each values,
which is coherent with the tolerance of usual components.
vic
The standard resistor/capacitor/inductance values are build the same wayWhy 0.47uf or 47uf? Is there a significance to that value or is it just a
randomly chosen value?
as music notes frequencies. For example the E12 series has 12 different
values between each decade, the factor between successive values is
calculated like this :
k = 10^(1/12) = 1.2115
V1 = 10 and Vn = k*V(n-1)
Which gives the following values (rounded)
calculated values: 10, 12, 15, 18, 22, 26, 32, 38, 46, 56, 68, 83, 100
E12 values : 10, 12, 15, 18, 22, 27, 33, 38, 47, 56, 68, 83, 100
For some reason there are slight differences but it's very close.
You can notice that there is about 20% difference between each values,
which is coherent with the tolerance of usual components.
vic
J
John Popelish
Guest
vic wrote:
--
John Popelish
E12 value 38 should be 36 and 83 should be 82JFS wrote:
Why 0.47uf or 47uf? Is there a significance to that value or is it just a
randomly chosen value?
The standard resistor/capacitor/inductance values are build the same way
as music notes frequencies. For example the E12 series has 12 different
values between each decade, the factor between successive values is
calculated like this :
k = 10^(1/12) = 1.2115
V1 = 10 and Vn = k*V(n-1)
Which gives the following values (rounded)
calculated values: 10, 12, 15, 18, 22, 26, 32, 38, 46, 56, 68, 83, 100
E12 values : 10, 12, 15, 18, 22, 27, 33, 38, 47, 56, 68, 83, 100
--
John Popelish
C
Clint Sharp
Guest
In message <Xns94DF7EB151FEEnonenonecom@24.93.43.119>, JFS
<none@none.com> writes
and a 7 in the value, if, on the rare occasion it still doesn't work,
get the test gear out. (Years of SMPS repair can do this to you!)
--
Clint Sharp
<none@none.com> writes
It's a basic rule of electronics repair, replace all components with a 4Why 0.47uf or 47uf? Is there a significance to that value or is it just a
randomly chosen value?
They had to think of a number to be the 'usual' fault and 47 got it.
and a 7 in the value, if, on the rare occasion it still doesn't work,
get the test gear out. (Years of SMPS repair can do this to you!)
--
Clint Sharp
G
Geir Klemetsen
Guest
But the value 38 becomes an E12 value of 39. 36 is too close to 33.E12 value 38 should be 36 and 83 should be 82
F
Fred Stevens
Guest
John Popelish <jpopelish@rica.net> wrote in message news:<40982308.65C128B2@rica.net>...
No, it should be 39.vic wrote:
JFS wrote:
Why 0.47uf or 47uf? Is there a significance to that value or is it just a
randomly chosen value?
The standard resistor/capacitor/inductance values are build the same way
as music notes frequencies. For example the E12 series has 12 different
values between each decade, the factor between successive values is
calculated like this :
k = 10^(1/12) = 1.2115
V1 = 10 and Vn = k*V(n-1)
Which gives the following values (rounded)
calculated values: 10, 12, 15, 18, 22, 26, 32, 38, 46, 56, 68, 83, 100
E12 values : 10, 12, 15, 18, 22, 27, 33, 38, 47, 56, 68, 83, 100
E12 value 38 should be 36 and 83 should be 82
V
vic
Guest
Sorry I should have checked ... the correct series isE12 values : 10, 12, 15, 18, 22, 27, 33, 38, 47, 56, 68, 83, 100
E12 value 38 should be 36 and 83 should be 82
No, it should be 39.
10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82, 100
G
GPG
Guest
k = 10^(1/12) = 1.2115 OK
V1 = 10 and Vn = k*V(n-1) no
Multipler = k^n For n = 0 to 11