Adding 2 caps together to make 1 value?

[Alan W]

Parallel caps are also often used to combine strengths—to the extent that many companies offer (well, used to offer, and may still?) single caps that included several bypass caps, all rolled into one package. Generally done for speed and phase related issues. Since (as guitar and bassists) we’re not all that interested in frequencies above 8 or 9K, you don’t see much bypass in general use.

 

[steviejr92]

It's a fantastic tool that I use nearly every day. You can download things like whole Fender tube amp models to get started: https://groups.io/g/LTspice

Even just using LTspice to archive build specs is pretty great, it's saved my butt quite a few times when I couldn't remember exactly what preamp format we used in a one off NAMM bass in 2018 or whatever.

Thank you so much for this! You’re motivating me to use start it up tonight!

 

[Passinwind]

Thank you so much for this! You’re motivating me to use start it up tonight!

The rabbit hole is deep, remember to come up for air occasionally!

 

[steviejr92]

Quoting this!

The rabbit hole is deep, remember to come up for air occasionally!

 

[fig]

Doing the math ourselves in never a bad idea IMO

I remember when they first allowed pocket calculators in classrooms. This may have been a game-changer had I still been in school. Who knows, I may have even passed Algebra.

 

[Passinwind]

I remember when they first allowed pocket calculators in classrooms. This may have been a game-changer had I still been in school. Who knows, I may have even passed Algebra.

Heh. I'm so old I remember having to use a slide rule when I took the SATs. I had been in the hospital until quite late the night before dealing with a knee injury from skiing and was a bit wacked out on Valium. When I re-took them a month later my scores didn't improve meaningfully either IIRC...

 

[jimilee]

This golden info for me i love learning ways around things. Exactly as you said its very liberating knowing i dont have to constrained anymore by *inbetween* values. So this is probably obvious but i should ask anyways this will work with resistors as well just use the teepee method?

I use the parallel method. To resistors in parallel will equal half the value. So, two 1M resistors in parallel=500k. I find it neater and easier to deal with than in series.

 

[jimilee]

I remember when they first allowed pocket calculators in classrooms. This may have been a game-changer had I still been in school. Who knows, I may have even passed Algebra.

Me and you both.

 

[jimilee]

Heh. I'm so old I remember having to use a slide rule when I took the SATs. I had been in the hospital until quite late the night before dealing with a knee injury from skiing and was a bit wacked out on Valium. When I re-took them a month later my scores didn't improve meaningfully either IIRC...

My fondest memories of the SATs is getting the results and deciding perhaps 6 years in a four year college was not for me.

 

[steviejr92]

I use the parallel method. To resistors in parallel will equal half the value. So, two 1M resistors in parallel=500k. I find it neater and easier to deal with than in series.

This is good to know!

 

[Alan W]

Heh. I'm so old I remember having to use a slide rule when I took the SATs. I had been in the hospital until quite late the night before dealing with a knee injury from skiing and was a bit wacked out on Valium. When I re-took them a month later my scores didn't improve meaningfully either IIRC...

One of my attempts at a weekly chore is the slow excavation through the detritus in our attic, where my goal is to wean away things we will never use again, of course not including anything I might be interested in in the future . Last week I unearthed my slide rule, a hand me down from an uncle, in its black leather sheath. Bamboo with I’m pretty sure machine engraved ivory cladding. I thought my son, who is a physicist, would enjoy it. He totally didn’t understand what it was for. It brought back memories of the giant slide rules that hung above the blackboards in school. (The slide rule went in the stack of “see if people pay money for these on eBay” items.)

We’re all relics. Those early HP calculators, that could just add, subtract, multiply and divide, started at about 1/3 the price of a Beetle when they first came out.

 

[Barry]

Me and you both.

Algebra was easy for me, I flunked Geometry couldn't get into Proofs and Theorem's

 

[Feral Feline]

@steviejr92 — Here's my goto online parallel-resistors/series-capacitor calc:

PARALLEL RESISTOR CALCULATOR

Jimilee gave a good example, 2X1M in parallel = 500k — but what if you've got a 1M and 820k resistors?
Using the online calc above, easy-peasy to figure out it gives you 450k.

There are quite a number of other websites that offer parallel resistor calculation — Digikey, I think, for example — find the one you like best.


What's really cool, as has been already referenced, is that the same resistors-in-parallel calcs work the same for capacitors in series. So a 470n feeding into a 390n ... baddaboombaddabang gives you 213n.

Just plug in the numbers and hit "calculate"... so easy even I can do it.

 

[steviejr92]

@steviejr92 — Here's my goto online parallel-resistors/series-capacitor calc:

PARALLEL RESISTOR CALCULATOR

Jimilee gave a good example, 2X1M in parallel = 500k — but what if you've got a 1M and 820k resistors?
Using the online calc above, easy-peasy to figure out it gives you 450k.

There are quite a number of other websites that offer parallel resistor calculation — Digikey, I think, for example — find the one you like best.


What's really cool, as has been already referenced, is that the same resistors-in-parallel calcs work the same for capacitors in series. So a 470n feeding into a 390n ... baddaboombaddabang gives you 213n.

Just plug in the numbers and hit "calculate"... so easy even I can do it.

Dude thank you so much for the link going to be using that for sure!