Hi Frank, where does the Fluke 3335b sit in the range of specifications?
M K > Date: Sat, 15 Dec 2012 12:38:00 +0100 > From: [email protected] > To: [email protected] > Subject: [volt-nuts] Fluke 335A/D > > Hello, > > according to the different documents for the 335A and the 335D, the 335A > had a mechanical chopper for the main error / chopper amplifier, and the > voltage reference consisted of a discrete (separate) zener and > transistor in an oven. > > The 335D already had the FET chopper and the TI or Motorola 'reference > amplifier', i.e. zener and transistor on-one-chip. > > Both versions obviously have the opto-chopper for the differential > voltmeter amplifier. > This is the same design as in the 845AR/AB. > > The 332D therefore is preferred over the 335A, and over the 332B, if the > differential voltmeter is needed. > Maybe it's easily possible to increase its sensitivity and damping to > 1µV instead of 10µV. > > I own a defective 332B/AF version (possibly AF = Air Force), which is > built the same as the 335D, only without the additional differential > voltmeter. > Its big problem is the high voltage pre regulator, as the supressor > Zener (CR14) and the switching transistor (Q1) are not available any > more. Therefore, a 5440/5442 was the best choice, especially as it has > Autocal; all the others need additional equipment for linearity and > range calibration. > > The HP 740B is also nice unit, but is has several neon bulb based > opto-choppers, which may be a big pain if they go defect. > > > Frank > > > _______________________________________________ > volt-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
