[EMAIL PROTECTED] wrote on 11/24/2008 08:31:22 PM: > Bruce wrote: > > Analog time constants of several hours are generally considered > > impractical due to the lack of suitable low noise components > > principally high value resistors and capacitors. > > So how do you propose to get around this with an analog control loop? > > Not too many years ago, high-impedance op-amps and teflon capacitors > were the way to do this. > > The op-amp companies had application notes discussing > "soakage"/dielectric > absorption in these circuits.
One can buy 10 microfarad metallized polypropylene capacitors new for about $20 each from Newark et al. The soakage of polypropylene is very small. Joe Gwinn _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
