xDevs.com is dedicated to electronics engineering, digital and analog circuit design, metrology, cryogenics, physics and calibration, PCB layout, FPGA and firmware development for embedded systems and devices. xDevs.com project does not have any monetary profit goals to achieve. There are no shareholders, board of directors or external sponsors behind xDevs.com project. This is by design to allow flexible projects management and rapid development of new ideas, without traditional business overheads.
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xDevs.com in-house projects and hardware
- KX Ultra-stable Voltage reference – public first generation of LTZ1000A 7V DC voltage standard
- Project 792X – 10V “FX” reference and Fluke 792A support pack – second generation of LTZ1000A-based ultra-stable DC Voltage standard
- Calibration procedure and results for xDevs/Fluke 792× 10V DC Reference – calibration procedure for FX-based standard
- LX DC Voltage reference with switching power supply block – third generation ADR1000-based zener reference
- QVR – Ultra-low noise DC Voltage reference – special quad-LTZ1000A reference module
- Neutron Power supply ATE – Power supply automated test system, 12-channel 2kW DC power rating for electronic load, 2% accuracy
- Development boards – ATMEL AVR, ARM, Altera CPLD and FPGA development opensource hardware kits
- Low-cost resistance transfer standard concept build
Calibration Festival meetups and interlab comparisons
- CalFest 2025 progress report
- CalFest 2024 progress report
- CalFest 2023 progress report
- CalFest 2022 progress report
- Calibration tests for Round 3 USA Cal Club
- SI units 2019 redefinition and TW NMI tour – Calibration transfers with Taiwan’s ITRI CMS National Metrology Lab
Resistance metrology
- Tinsley 5685A resistance standards review
- Fluke 742A resistance standards repairs and performance checks
- Study of temperature stability, more than 260 resistors – Methodology and test results of various commercial precision resistors
- Fluke SL935 heated resistance standard prototype
- ESI SR104 10000 Ohm resistance standard review
- DIY 10kΩ reference resistor
- Guildline 6675A/6623 resistance bridge system and experiments
- Benchmarks of old L&N 4040B 10000 Ohm resistance standard
- High-current low resistance and shunt measurements log
- Resistor ratio dividers based on N equal resistors
- Repair and review of Guildline 9330 standard resistor
- Review and benchmarks of Julie Research Labs 1 Ω CH48T4HK resistor elements
DC Voltage metrology
- LTZ1000CH voltage reference – A simplified version of Wavetek/Fluke 7000
- Tale 2 : eBay LTZ1000A reference modules and caveats
- Wavetek 7000 cell reference testing
- Tale 1 : Little jumper, or sharks in voltage references world
- Keithley 262 low thermal divider overhaul
- Datron 4910 series DC voltage reference repair 4910 series DC voltage reference repair
- Keithley 7168 nanovolt switch card and it’s use with RPI
- DataProof 160A low thermal EMF scanner teardown
- Review and application of EM A10 nanovolt amplifier
AC\DC Voltage metrology
- Fluke 792A AC/DC transfer standard repair – Repair of battery block and testing of Fluke 792A metrology AC/DC transfer standard.
- Wavetek 4920M AC standard repair – Repair and calibration of Wavetek 4920M AVMS.
- Fluke 5790A AC Measurement Standard repair
- Review and experiments with Ballantine 1394N TVC kit
Low currents/high resistance metrology
- Keithley 6430/4200 preamplifier teardown and stand-alone use options
- Keithley 6517A electrometer restoration project
- HP 16340A RC calibration box for electrometers
RF equipment
- Agilent E8251A PSG-A 20 GHz analog signal generator repair
- Agilent N5161A MXG ATE RF Analog Signal Generator repair and benchmarks
- Leo Bodnar’s fast pulser (2.92mm version) review
Thermometry and environmental instrumentation
- Keithley 2510 repair – Repair and calibration of Keithley Model 2510 TEC SMU
- Large DIY environmental chamber for DMM/T&M gear testing
- Arroyo TECpak temperature controller unit review and usage
- Building air-bath thermal Peltier chamber
- Using BME280 temperature/humidity/pressure sensor with Raspberry Pi
- Fluke 1529 Chub-E4 precision thermometer readout
Calibrators, repairs and applications
- Fluke 5700A calibrator overhaul – Service and minor repairs for high-end 7½-digit Fluke 5700A series calibrator.
- Fluke 5700A/NAF units repair and troubleshooting – Service of 5700A/NAF units
- Wavetek/Datron 4808 multifunction calibrator restoration log – Service for 7½-digit Wavetek 4808 calibrator.
- Time Electronics 9823 AC-DC calibrator repair – Service for 5½-digit Time Electronics calibrator.
8½-digit DMMs, repairs and reviews
- Agilent 3458A HFL repair
- Keysight 3458A RoHS Black Edition DMM review and evaluation
- HP/Agilent/Keysight 3458A repair worklogs – Detailed worklog covering HP 3458A 8½-digit DMMs repair and upgrades
- HP/Agilent/Keysight 3458A 8.5-digit DMM modifications and tweaks
- HP 3458A second unit service and rebuild – Worklog covering second HP 3458A 8½-digit DMM
- HP 3458A repair for a friend – Third article with HP3458A repairs.
- HP 3458A repair and FRAM upgrade by TEKTRON – FRAM upgrade and other experiments from TEKTRON
- Project P3459, building high-end DMM by using scrap 3458A parts – Work in progress on experiments with HP3458A hardware.
- Datron 1281 DMM repair and calibration worklog – worklog covering two Datron/Wavetek 1281 8½-digit DMMs repair and upgrades
- Keithley 2002 repair – Extensive repair experience for Keithley Model 2002 8½-digit precision multimeter
- Keithley 2002 review – Teardown and review of Keithley Model 2002 8½-digit precision multimeter
Cryogenics and instrumentation
ADC \ DAC and acquisition hardware
- Texas Instruments ADS1262 32-bit ADC evaluation, intro
- Evaluation of Linear DC2390A – Linear LTC2500-32 32-bit SAR ADC solution
Software and automation
- HP 3458A GPIB remote control guide
- Using Agilent/Keysight E5810A with python
- Setting up and using Agilent 82357B GPIB USB pod in RPi Linux
- Setting up and using NI USB-GPIB-HS in Raspberry Pi Linux
- xDevs.com CalKit automation software manual
- Using ALTERA/Terasic DE1-SoC (Cyclone V SE FPGA SoC) kit for linux-gpib
Test equipment repairs and reviews
- Replacement of the lamp backlit LCD for new high-contrast type in MIL 6010B
- INL (Integral non-linearity) performance testing
- DMM noise measurement – public project to measure and compare noise of bench multimeters.
- Keysight B2987A electrometer teardown – Brief look on high-performance electrometer design
- Keithley 2001 repair – Repair experiences with multiple Keithley Model 2001 7½-digit precision multimeters
- Keithley 2400 repair – Repair of broken VFD glass and testing Keithley Model 2400 SourceMeter
- Notes on Keithley DD-51 dual-line VFD replacements
- Repair of Keithley 2425 100W SMU
- Keithley secret menu and settings
- HP/Agilent/Keysight 34420A Nanovoltmeter repair
- HP 3245A Universal source repair – Repair and calibration of rare HP 3245 precision 6½-digit DC/AC signal source
- HP 3456A digital voltmeter restoration
- Tweaks and mods for HP 3457A 6.5-digit DMM
- Evaluation of modern pressure sensors with digital interface
- How to recover white color of old plastic panels and buttons
- Fluke 8842A repair and calibration
- HP 34401A repair and calibration worklog
- Agilent 4142B semiconductor SMU system repair and usage
Oscilloscopes and digital logic
- Review and tests of Femto HVA low-noise amplifier
- Leo Bodnar’s fast pulser (2.92mm version) review
- Tektronix ADA400A Differential Preamplifier repairs
- Repair and teardown of Tektronix TMDP0200 and THDP0100 probes
- Repair and PC HW ugrades for TDS5000B series scope
- Tektronix TDS7000 series repair
- Teardown and repair of Tektronix TDP1000 differential 1 GHz probe
- SensePeek SP200 passive probe review
- Benchmarks and performance of Teledyne LeCroy ZS1500 active single-ended probe
- Picotech TA061 SMA passive probe review
- Teledyne LeCroy PP023 passive probe review
CPU & GPU Overclocking and guides
- Overclocking for Raspberry Pi 3 Model B with liquid nitrogen
- Extreme OC toolkit for EVGA GeForce GTX 3090 K|NGP|N
- EVGA RTX 2080 Ti KINGPIN Edition Technical Guide
- EVGA GTX 1080 Ti K|NGP|N Edition graphics card
- Reference GTX 1080 Ti – Uncorking bigger Pascal
- Reference GTX 1080/1070 – Uncorking Pascal
- Teardown of the EVGA GeForce RTX 2080 Ti XC Ultra
- EVGA GTX 980 Ti K|NGP|N OC Guide
- Extreme OC modifications for NVIDIA GeForce GTX 980
- Using Raspberry Pi to control EPOWER VRM
- Review of NVIDIA Titan V design and power benchmarks
- Design guide for EVGA Z390 DARK motherboard
- Overclocking guide for EVGA X299 DARK motherboard
- Review and usage of EVGA EPOWER V power module