Should I be paying more attention to the ESR of my Electrolitic Caps

[Peter Venkman]

Just what The tittle says. Im confused as all get out about what my ESR should be for electrolytic Caps and have been unable to find a good rule of thumb for what ESR rating to look for on these caps in different portions of circuits. Can anybody explain like im 5?

[Ciaran Haslett]

Short answer is no.  The perfect capacitor passes AC signals at ALL frequencies.  But caps are not perfect.  They can appear as a resistance to very high frequencies (electro caps dry out over time and this high freq resistance begins to get wider) well out of the audio range.

So for our purposes, no it doesn't matter., unless you're building radio receivers or high performance power supplies.  So don't waste your money on low ESR caps if you're planning on using them in a dirt box...or any pedal really

[Peter Venkman]

Thanks man. You have helped me multiple times on here and I appreciate that a lot. I know that when Im doing service work on old radios, amplifiers, and other tube stuff, I need to be paying attention to it, but wanted to make sure I wasn't being stupid about ignoring it in my pedals.

I work in an electronics components shop and Ive asked a few of our regular customers about the electrolytic cap ESR "rule of thumb" and every single person gave me different answers. I just wanted some sort of formula to apply when working in an amp, like if the Electrolytic Cap is a 47uF the ESR needs to be within a range of ________ to ________ ohms. Just like a multiplier to apply to any value of cap to give me a good average for the cap to stay within. We get every kind of customer from audiophiles to first time DIY guys, to electrical engineers with masters degrees in capacitor manufacturing, and not a single person I asked could answer my question without a 45 minute diatribe on the definition and applications of ESR values and their effects on circuits. Some times people don't understand your question so they just go off on a tangent that is basically a broad generalization of the subject, never really giving an answer.

You rule thanks again.