Re: [volt-nuts] Ayrton Shunt does double duty.

Built a small temperature chamber using a Starbucks Refrigerator, Yokogawa Temperature controller, and PTC Heater (300 watt). It covers 0 degrees C to 55 degrees C and has an RS-485 interface to the PC. The compressor runs all the time, and the controller cycles the 300 watt heater as needed t

Re: [volt-nuts] Precision high resistance measurements / calibration of HP 4339B high-resistance meter.

Here are specs from an older General Radio Bridge for observation. GR 1644-A specifications: Resistance Range: 1 kΩ to 1000 TΩ (10^3 to 10^15 Ω) in ten ranges. Accuracy: 10^3 Ω to 10^10 Ω, ±1 %. After self-calibration: 10^10 to 10^12 Ω, ±1%*; 10^13 Ω, ±2%; 10^14 Ω, ±10%; 10^15 Ω, ± one scale divi

Re: [volt-nuts] Best way to measure micro Ohms

I once repaired a Valhalla 2555A Current Calibrator (good for up to 100A output). It uses aluminum bus bars inside to route the current. The junctions between the bars had become higher than normal impedance and it could no long

Re: [volt-nuts] Best way to measure micro Ohms

The Keithley 2002 uses DC but automatically takes a reading of any offset voltage and subtracts it (offset compensation). Rated accuracy on the 20 ohm range (2 years) is +/- 26 ppm, and with 10 averages it has a resolution of 0.1 microohms. Best regards, mitch -Original Message- Fro

Re: [volt-nuts] Current Button for Datron calibrator (4800, 4805, 4807, 4808)

Last time I dealt with the Fluke Service center in the US, they had a minimum order of $300. -Original Message- From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of David C. Partridge Sent: Monday, July 03, 2017 2:23 PM To: 'Discussion of precise voltage measurement' Subject:

[volt-nuts] Valhalla 2701B

Hello, Just wanted to mention to the group today I listed a Valhalla 2701B DC Calibrator on eBay. I have used this unit for about six years and it works very well except the HPIB does not work. It has full-scale ranges from 1.2V to 1200V and each knob goes from 0 - 11. Bought a 2701C so I no

Re: [volt-nuts] Sorry: Low-cost Josephson Junction Array Corrected link

Guys, The Fluke DVMP Care Plan will give you the ability to know the value of your best voltage standard, and it's drift rate, at FAR less expense than buying your own JJA: http://download.flukecal.com/pub/literature/2001531_A_w.pdf It will give you results with about HALF the uncertainty comp

Re: [volt-nuts] Practical power supply noise testing

Hi John, A simple check is to measure the output with an HP 3400A or HP3400B. These are true RMS meters (AC coupled) with 10 Hz to 10 MHz BW and capability to handle VERY high crest factors and still give an accurate readings. They go down to 1 mV FULL-SCALE which should be sensitive enough f

Re: [volt-nuts] Suggestions for 10 milli Ohm 0.04 % 100 W resistor

Hello David, This seller is offering a lot of ten (10) 0.1 ohm 10W 1% wirewound resistors. These resistors are quite stable and have a fairly low temperature coefficient. I believe you could fabricate a 0.01 ohm +/- 0.04% resistor (after trimming) that could easily handle 9W and do the job.

Re: [volt-nuts] Agilent 34401A Dim Display

Hello Dave, Some users leave them on 24/7 which does wear the display out and makes it dimmer. If you are going to use the unit over HPIB under computer control, it may not matter that much. They are a really fine meter and I think you will not be disappointed. Best regards, mitch -Or

Re: [volt-nuts] Precision resistor testing

Hi Dick, I have a small temperature chamber and can create plots characterizing the resistor like the one attached. Best regards, mitch -Original Message- From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of Richard Moore Sent: Friday, November 14, 2014 5:36 PM To: volt-nu

[volt-nuts] Using a DVM to adjust a 752A divider

Folks, Had some correspondence with Fluke a while back regarding adjustment of the 752A Reference Divider. They no longer sell the 845AB Null Detector but they have some suggestions on alternate meters to do the job. They also make reference to zeroing the inputs of the detector, which has be

Re: [volt-nuts] Need info on L&N 4214 temp vs resistance plot..

Hi Willy, For what it's worth I have attached the resistance vs. temperature curve for my 10 k Rubicon which is of similar construction. It has a peak at about 23.5 degrees C. Best regards, mitch -Original Message- From: volt-nuts-boun...@febo.com [mailto:volt-nuts-boun...@febo.com] On

Re: [volt-nuts] AC Voltage Measurement Standards

Joe, I used a Fluke 540 for a while, and also the Fluke 8506A. The Fluke 540 is MUCH more difficult to use. You need to flip the switch between two positions rapidly and the results you get depend somewhat on how "rapidly" you make the transition. For AC volts the 8506A seems very nice. Best re

Re: [volt-nuts] Another LED display wanted...

Is one used as an exponent, and doesn't need all segments to work? -Original Message- From: volt-nuts-boun...@febo.com [mailto:volt-nuts-boun...@febo.com] On Behalf Of Mark Sims Sent: Tuesday, June 03, 2014 5:26 PM To: volt-nuts@febo.com Subject: [volt-nuts] Another LED display wanted...

Re: [volt-nuts] Solartron 7071 on ebay UK

Amazing! -Original Message- From: volt-nuts-boun...@febo.com [mailto:volt-nuts-boun...@febo.com] On Behalf Of Robert Atkinson Sent: Thursday, February 27, 2014 12:13 PM To: Discussion of precise voltage measurement Subject: Re: [volt-nuts] Solartron 7071 on ebay UK Well  the 7071 (ebay it

Re: [volt-nuts] Question for Fluke 732A owners

If you put a 34401A in the high-input impedance mode you can fairly accurately measure the battery voltage from the outside across two of the pins. -Original Message- From: volt-nuts-boun...@febo.com [mailto:volt-nuts-boun...@febo.com] On Behalf Of T. Micallef Sent: Wednesday, February 26,

Re: [volt-nuts] Question for Fluke 732A owners

Male contacts (3) -Original Message- From: volt-nuts-boun...@febo.com [mailto:volt-nuts-boun...@febo.com] On Behalf Of Charles Steinmetz Sent: Wednesday, February 26, 2014 5:47 PM To: VoltNuts Subject: [volt-nuts] Question for Fluke 732A owners Fluke used two different connector schemes f

Re: [volt-nuts] HP 3457A

In 2002 I bought a used HP 34401A. Sent it in to Agilent (Loveland, CO) for calibration in March 2005 and they sent it back with both "as found" and "as left" sets of data. This is what the "as found" data said: 100mV = -4 ppm 1.0V = +3 ppm 10.0V = +5 ppm 100V = +4 ppm 1000V = +6 ppm They adjus

Re: [volt-nuts] VS 330 circuit board oddity

The module's pins fit into the little gold cups which are soldered to the traces. It is an individual "socket" for each pin. The Ty-wrap is to insure the module doesn't pop out during shipment. Regards, mitch - Original Message - From: "Joseph Gray" To: "Discussion of precise vol

Re: [volt-nuts] What really gets calibrated? A reference

I too, highly recommend this book. Once I started reading it I couldn't stop, and read it from cover to cover probably twice. Regards, Mitch - Original Message - From: "Robert Atkinson" To: "Discussion of precise voltage measurement" Sent: Monday, July 29, 2013 2:28 PM Subject: Re

Re: [volt-nuts] Voltage to frequency

Virtually all of the adjustable calibrators from Fluke, Valhalla, and others do a PWM to precision voltage conversion. Regards, Mitch - Original Message - From: "Steve - Home" To: "Discussion of precise voltage measurement" Sent: Monday, July 29, 2013 4:09 PM Subject: Re: [volt-nut

Re: [volt-nuts] Semi-precision high resistance measurement

Hi Steve, I would suggest two things. First, place the 8050A on it's most sensitive DC range and see if it indicates any voltage across the resistor. Assuming there is nothing present, then I would suspect AC pickup on the meter leads and a path to ground that is a different impedance from o

Re: [volt-nuts] Keithley 2002 schematic

Hi Jeff, I just fixed mine which had a similar problem. The manual does have a description of the power supply but there are a few errors in the component designators. The schematic seems impossible to get through regular channels but I managed to sketch out the majority of the AC input stru

Re: [volt-nuts] LTZ1000 reference appnote question

Positive input voltage range for an LT1006 is typically 1.2V below the positive rail. mitch - Original Message - From: "Fabio Eboli" To: Sent: Wednesday, November 07, 2012 7:02 PM Subject: [volt-nuts] LTZ1000 reference appnote question Hello, in this thread on eevblog: http://w

Re: [volt-nuts] 732 and 752 recently on ebay

I saw them...they looked very clean. From my observation they normally go for about U.S. $500 each, so it does seem like a high price for the pair. mitch - Original Message - From: "m k" To: Sent: Saturday, November 03, 2012 8:32 AM Subject: [volt-nuts] 732 and 752 recently on eba

Re: [volt-nuts] Thermistor value for 732A Reference 10V Standard

I think monitoring the 1V or 1.1V is a better test over temperature than monitoring the 10V. It's quite stable even without the heater. - Original Message - From: "Rob Klein" To: "Discussion of precise voltage measurement" Sent: Friday, June 29, 2012 6:29 AM Subject: Re: [volt-nuts

Re: [volt-nuts] Thermistor value for 732A Reference 10V Standard

Hi Tom, According to the Fluke 732A manual page 2-6 the nominal value is between 3k - 4k with the oven at normal operating temperature. Mine checks 3.545 k and has been within a few ohms of that reading each year for five years. You may have a heater problem. There is a protective thermal fu

Re: [volt-nuts] Help with 7081 AC buffer circuit

David, Try enclosing the op-amp and nearby components with a little Styrofoam "hat". The part dissipates a fair amount of power and the bias current, although small, does show significant change with temperature. This change multiplied by the 1 megohm input resistor may be responsible for so

Re: [volt-nuts] keithley 2015 (2000) voltage reference SL40057

The Keithley 2002 Service Manual says it uses a "IC, ULTRA PRECISION REF, LT21000A (PKG H8)". Regards, Mitch - Original Message - From: "Andreas Jahn" To: "Discussion of precise voltage measurement" Sent: Sunday, May 27, 2012 4:57 AM Subject: Re: [volt-nuts] keithley 2015 (2000)