Re: [time-nuts] Replacement A9 boards for the HP 5065A

It depends on the quantity they buy. I just looked for X7R 0.1uF in 0805 at Digikey and the automotive grade (10%, -55 to +125) is cheaper than the non automotive grade with worse tolerance and more limited temperature range. Next time you buy it may be reversed... On Feb 25, 2018 1:51 PM,

Re: [time-nuts] Replacement A9 boards for the HP 5065A

On Sun, Mar 4, 2018 at 1:04 PM, Charles Steinmetz wrote: > So, no PTFE or PS for practical reasons. That leaves us with PP, PPS, and > perhaps PC. These all have reasonably similar DA, so as long as one checks > the particular capacitor's datasheet to verify, DA should

Re: [time-nuts] Replacement A9 boards for the HP 5065A

Poul-Henning wrote: I fully agree, and if it were me, I would absolutely use the best capacitor I could find at a non-insane price. But that was exacly my point: The only thing you (might!) get by spending an *insane* amount of money on that capacitor is PTFE and its better dielectric

Re: [time-nuts] Replacement A9 boards for the HP 5065A

In message <5a9c4644.5030...@yandex.com>, Charles Steinmetz writes: >Some times, "just because it's better" is a sufficient >reason to overdesign, particularly where the incremental cost is low and >especially where the projected number of units is low, both of which are >true WRT the

Re: [time-nuts] Replacement A9 boards for the HP 5065A

Poul-Henning wrote: The input signal to the integrator is continuous and jump-free and the relevant time constant is sub-second. Dielectric absorption doesn't matter when there are no voltage jumps. That is a very common misconception, probably fostered by the usual test methodology for DA.

Re: [time-nuts] Replacement A9 boards for the HP 5065A

Group, After 40 years of doing PID control for industrial processes, I'm used to an error tolerance of 10E-3. So I couldn't understand an integrator with a 10 K resistor and a 5 mfd capacitor. But this is time nuts, and the tolerance is more like 10E-13. An integrator as a controller takes any

Re: [time-nuts] Replacement A9 boards for the HP 5065A

In message , Wayne Holder writes: >>> The only thing I could provok, was that almost all capacitors I >>> tried were sensitive to touch. > >Most ceramic caps are sensitive to "micro phonics" via the piezoelectric

Re: [time-nuts] Replacement A9 boards for the HP 5065A

>> The only thing I could provok, was that almost all capacitors I >> tried were sensitive to touch. Most ceramic caps are sensitive to "micro phonics" via the piezoelectric effect, which can translate mechanical stress into electrical noise.

Re: [time-nuts] Replacement A9 boards for the HP 5065A

In message

Re: [time-nuts] Replacement A9 boards for the HP 5065A

Well all this capacitor talk has me actually looking for the 5 uf cap. When I picked up the 5065a it didn't work. This was in the late 90s and no manual was available at that time. I reverse engineered the system and guess what cap was bad? The integrator. So not being all that smart, I hooked 2 X

Re: [time-nuts] Replacement A9 boards for the HP 5065A

time-nuts@febo.com> Subject: Re: [time-nuts] Replacement A9 boards for the HP 5065A On Sat, 24 Feb 2018 23:44:16 -0500 Charles Steinmetz <csteinm...@yandex.com> wrote: > Given the relatively low resistances at the op-amp inputs (10k ohms), > the ultra-low input "bias" (leak

Re: [time-nuts] Replacement A9 boards for the HP 5065A

On Sat, 24 Feb 2018 23:44:16 -0500 Charles Steinmetz wrote: > Given the relatively low resistances at the op-amp inputs (10k ohms), > the ultra-low input "bias" (leakage) current of the 6240 is simply > unnecessary. Any offset due to the input currents (within the

Re: [time-nuts] Replacement A9 boards for the HP 5065A

Am 25.02.2018 um 13:46 schrieb Azelio Boriani: The part number BFC234421475, on seems to be a Philips product, 2500 available, for 49.28 UAH (Ukrainian Hryvnia, that is 1.77 USD). A mysterious capacitor... Why not go to Mouser or DK, as usual? Or to the

Re: [time-nuts] Replacement A9 boards for the HP 5065A

The part number BFC234421475, on seems to be a Philips product, 2500 available, for 49.28 UAH (Ukrainian Hryvnia, that is 1.77 USD). A mysterious capacitor... On Sun, Feb 25, 2018 at 12:35 PM, Charles Steinmetz wrote: > Interesting.

Re: [time-nuts] Replacement A9 boards for the HP 5065A

Interesting. I'm inclined to say I stand corrected, BUT: (i) as Mark noted, the datasheet link points to the datasheet for Vishay FC Series HF thin-film resistors [which are really excellent low-reactance T/F resistors, if you need any]; (ii) I cannot find any reference to PC caps on the

Re: [time-nuts] Replacement A9 boards for the HP 5065A

From: Bill Hawkins <bill.i...@pobox.com> Date: 2/24/18 10:26 PM (GMT-05:00) To: 'Discussion of precise time and frequency measurement' <time-nuts@febo.com> Subject: Re: [time-nuts] Replacement A9 boards for the HP 5065A Corby A time constant is calculated from R a

Re: [time-nuts] Replacement A9 boards for the HP 5065A

Returning to the topic of what op-amp to use: Bert asked if the LT1793 is a good choice. I suggested the LT1012 as superior in the specific parameters that will provide best performance in the HP circuit (https://www.febo.com/pipermail/time-nuts/2018-February/108964.html). Attila suggested

Re: [time-nuts] Replacement A9 boards for the HP 5065A

The key properties relevant to long-TC integrator capacitors are insulation resistance (leakage) and dielectric absorption (DA). (One response on this thread opined that DA is not important in this circuit, but that is not correct. DA is most definitely a factor in long-TC integrators,

Re: [time-nuts] Replacement A9 boards for the HP 5065A

Corby A time constant is calculated from R and C. If 50 milliseconds is the correct number, R for 5 mfd is 10,000 ohms. You could use an aluminum electrolytic for the capacitor. Can you tell us where the 50 ms number came from? Regards, Bill Hawkins -Original Message- From:

Re: [time-nuts] Replacement A9 boards for the HP 5065A

Am 25.02.2018 um 00:45 schrieb cdel...@juno.com: Hi, I'm working to make some replacement A9 boards for the HP 5065A to the new style schematic. Will share the Gerber file when done. The integrator capacitor is a 1986 vintage TRW 5.0ufd 50V 10% .42"DX1.0"L axial. Of course it has an HP

Re: [time-nuts] Replacement A9 boards for the HP 5065A

Not too long ago I designed an integrator for a piezoelectric force transducer. The customer wanted a rock-solid output after a step load on the transducer. The capacitor of choice was PPS, used in surface mount form and less than 0.5uF total capacitance. With a particular PCB material chosen

Re: [time-nuts] Replacement A9 boards for the HP 5065A

Hi Teflon is the traditional “best of the best” for integrator caps. Simply finding any plastic cap (other than a motor start device) up around 5 uf is not that easy these days. As mentioned by PHK, being sure it is what it’s supposed to be …. good luck. Bob > On Feb 24, 2018, at 6:45

Re: [time-nuts] Replacement A9 boards for the HP 5065A

In message , cdel...@juno.com writes: >Any guess as to what type it is? > >Polycarbonate, polypropylene, ??? I think the manual says polypropylene in the parts list ? >Just wanting to find a good modern replacement for its use. (Integrator