Capacitors

[Gtrjunior]

Re: Capacitors

This is why I think guitar caps should be spoken as nanofarads. It's much easier to get right 47 than 0.047

Why anyone even uses that annoying measures?

It’s crazy that we all don’t use the same measuring system!!
When I was a kid, we were told that eventually the US would transition over to the metric system....still hasn’t happened. Lol
The only difference now is that there are 2 measurement systems in place here.
Stuff imported from other countries typically are in the metric system and stuff made domestically isn’t.
Go figure.

 

[Darg1911]

Re: Capacitors

I just buy .022 and stack them if I need a .044

Stacking caps is the opposite of stacking resistors
Two resistors in parallel are one quarter the total resistance of the pair
Two caps in parallel are the sum of the two cap values

Two resistors in series are the sum of all resistance values
Two caps in series are one quarter the sum

Two clarifications ...

Two caps in series are only 1/4 the sum of the values if the values of both caps are the same.
Two resistors in parallel are only 1/4 the sum of the values if the values of both resistors are the same.

 

[Chistopher]

Re: Capacitors

It’s crazy that we all don’t use the same measuring system!!
When I was a kid, we were told that eventually the US would transition over to the metric system....still hasn’t happened. Lol
The only difference now is that there are 2 measurement systems in place here.
Stuff imported from other countries typically are in the metric system and stuff made domestically isn’t.
Go figure.

I find empirical measurements are better for manufacture because it has a unit between inches and yards that isn't as small and useless as decimeters (which is so rarely used it didn't even show up in my phones dictionary). But for anything over 10 meters or under 1 inch, I prefer metric. All other measurements I prefer the American way.

 

[Artie]

Re: Capacitors

Two resistors in parallel are one quarter the total resistance of the pair.

Two clarifications ...

Two caps in series are only 1/4 the sum of the values if the values of both caps are the same.
Two resistors in parallel are only 1/4 the sum of the values if the values of both resistors are the same.

Sorry guys, but's it's half. Not quarter. Ergo, two 500k resistors in parallel is 250k. Same for caps. Half, not quarter. (When in series.)

 

[Jacew]

Re: Capacitors

It’s crazy that we all don’t use the same measuring system!!
When I was a kid, we were told that eventually the US would transition over to the metric system....still hasn’t happened. Lol
The only difference now is that there are 2 measurement systems in place here.
Stuff imported from other countries typically are in the metric system and stuff made domestically isn’t.
Go figure.

Yep. Need to have two sets of tools even here...

That isn't the issue I meant though, unit is the same.

When talking capacitors in guitars, why you have to stick with microfarads? That's like measuring lenght of your house in miles.

1 microf = 1000 nanof. So 0.047 = 47 nf

 

[Jacew]

Re: Capacitors

Sorry guys, but's it's half. Not quarter. Ergo, two 500k resistors in parallel is 250k. Same for caps. Half, not quarter. (When in series.)

And two caps in parallel are the sum of their value like ehdwuld said.

 

[Artie]

Re: Capacitors

And two caps in parallel are the sum of their value like ehdwuld said.

Yup. And I've always wondered about the cap value thing. I've never understood the reluctance to use the nano prefix. A cap will either be .022 uf's or 22,000 pf's. :dunno:

 

[Darg1911]

Re: Capacitors

Sorry guys, but's it's half. Not quarter. Ergo, two 500k resistors in parallel is 250k. Same for caps. Half, not quarter. (When in series.)

Yes, it's half the stated value of the resistors IF both resistors are the same value. That wasn't exactly what Ehdwuld wrote. He wrote that it was 1/4 of the SUM of the values. Both is correct but ONLY when the values of the two resistors (or caps, in series) are the same. I believe that he wrote it the way in which he did because he thought that the "rule" (incorrect) held when the two resistors (or caps, in series) were of different values as well. But that's an assumption on my part.

Read it again.

 

[Darg1911]

Re: Capacitors

Sorry, Double post.

 

[ehdwuld]

Re: Capacitors

I just assumed we were talking about like values

Two 500k resistors equal 1000k as the sum
250k is one quarter of 1000k as stated

Like I said one quarter the sum

Thank you

I believe stacking caps of whatever value in parallel is like like stacking resistors in series and vice versa
I have put resistors on pickups to alter the resistance
And I still have found the statement I made to be accurate for the most part

Thank you for clarifying
One must test the stack to verify the results

I spend a lot of my day with EEs and PhD EEs
I believe I got the math correct

 

[Darg1911]

Re: Capacitors

I just assumed we were talking about like values

Two 500k resistors equal 1000k as the sum
250k is one quarter of 1000k as stated

Like I said one quarter the sum

Thank you

I believe stacking caps of whatever value in parallel is like like stacking resistors in series and vice versa
I have put resistors on pickups to alter the resistance
And I still have found the statement I made to be accurate for the most part

Thank you for clarifying
One must test the stack to verify the results

I spend a lot of my day with EEs and PhD EEs
I believe I got the math correct

Yes, it's correct if the values are the same but it would be more simply stated by saying it's half the value of one of the resistors. It's the same result as summing the values and dividing by 4. Pretty sure that's where the confusion comes from. No biggie.

 

[beaubrummels]

Re: Capacitors

We need an EE-approved basic guitar electronics sticky thread.

Could be culled from all the past 10 years of conversations on here maybe.

 

[Chistopher]

Re: Capacitors

We need an EE-approved basic guitar electronics sticky thread.

Could be culled from all the past 10 years of conversations on here maybe.

It should be prefaced with "If you're only education of the finer elements of electronics is from reading other threads, you shouldn't parrot that information unless you at least consult another source to confirm it." It must also include a thorough lecture about DCR.

 

[Artie]

Re: Capacitors

Ah . . . good catch guys. I completely missed the "sum" part.

 

[Jacew]

Re: Capacitors

Maybe it would be clearest to simply state it as it is correctly calculated:

All cap values multiplied and divided by sum of same values.

ie: (C1 × C2)/(C1 + C2) = total

 

[Darg1911]

Re: Capacitors

Maybe it would be clearest to simply state it as it is correctly calculated:

All cap values multiplied and divided by sum of same values.

ie: (C1 × C2)/(C1 + C2) = total

Hell, there are online calculators for that. :bigthumb:

 

[Jeff_H]

Re: Capacitors

Aww, what happened to Bodeanicus? I was really enjoying the input.

 

[DavidRavenMoon]

Re: Capacitors

Sorry guys, but's it's half. Not quarter. Ergo, two 500k resistors in parallel is 250k. Same for caps. Half, not quarter. (When in series.)

I was going to say this too, but he said one quarter the total resistance, e.g., 500k X 2 = 1,000 ohms.


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[DavidRavenMoon]

Re: Capacitors

Yep. Need to have two sets of tools even here...

That isn't the issue I meant though, unit is the same.

When talking capacitors in guitars, why you have to stick with microfarads? That's like measuring lenght of your house in miles.

1 microf = 1000 nanof. So 0.047 = 47 nf

I like microfarads better. It’s easier to visualize.

Some people get carried away with metrification. Lol.

I use both mm and inches when I’m workin on certain things. Millimeters are a handy small unit, but so is 64ths of an inch!

And why would I want to say 15.875mm instead of 5/8” which is easy to see on my rule.


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[Jacew]

Re: Capacitors

I like microfarads better. It’s easier to visualize.

Some people get carried away with metrification. Lol.

I use both mm and inches when I’m workin on certain things. Millimeters are a handy small unit, but so is 64ths of an inch!

And why would I want to say 15.875mm instead of 5/8” which is easy to see on my rule.


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Not going to mention whole fractions vs. floating point numbers issue...

But how do you visualize farads?