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From: plumpe@oasys.dt.navy.mil (David Plumpe)
Newsgroups: sci.electronics
Subject: Re: Making up odd resistor values required by filters
Message-ID: <34738@oasys.dt.navy.mil>
Date: 22 Apr 93 15:08:11 GMT
References: <1993Apr22.134348.2663@nessie.mcc.ac.uk>
Reply-To: plumpe@oasys.dt.navy.mil (David Plumpe)
Organization: Carderock Division, NSWC, Bethesda, MD
Lines: 14

In sci.electronics, idh@nessie.mcc.ac.uk (Ian Hawkins) writes:
>When constructing active filters,  odd values of resistor are often required
>(i.e. something like a 3.14 K Ohm resistor).(It seems best to choose common
>capacitor values and cope with the strange resistances then demanded).
>
>Is there a PD program out there that will work out how best to make up such
>a resistance, given fixed resistors of the standard 12 values per decade?.(1,
>1.2,1.5,1.8,2.2,3.3 etc ).  It is a common enough problem,  yet I cant
>recall seing a program that tells that Rx+Ry//Rz gives Rq,  starting with
>q and finding prefered values x,y and z.

    Since you're worrying about the third decimal place, I assume you're
using 1% tolerance resistors and capacitors?

