Yoke JA-C Advanced Precision Balance

Overview

The Yoke JA-C Advanced Precision Balance is an entry-level analytical-grade weighing instrument engineered for laboratories requiring consistent 1 mg readability across a 500 g maximum capacity. It employs electromagnetic force restoration (EMFR) sensor technology—a principle in which the downward gravitational force of a sample is counterbalanced by a precisely regulated electromagnetic field, enabling direct mass measurement without mechanical levers or pivots. This architecture delivers high reproducibility, minimal drift, and long-term stability under standard laboratory conditions (20–25 °C, <60% RH). Designed for routine QC testing, formulation support, sample preparation, and educational use, the JA-C meets foundational metrological requirements for non-regulated environments while providing traceable internal calibration functionality. Its robust cast-aluminum base and optimized thermal mass distribution minimize sensitivity to ambient air currents and minor floor vibrations—key considerations for benchtop precision balances operating without draft shields in shared lab spaces.

Key Features

• Electromagnetic force restoration (EMFR) transducer system ensuring linearity, low hysteresis, and zero mechanical wear over extended service life.
• Internal calibration mechanism with automatic temperature-compensated self-adjustment—initiated via front-panel keypress or scheduled interval (user-configurable).
• Large backlit LCD display (128 × 64 pixels) with high-contrast characters and adjustable brightness for optimal legibility under varied lighting conditions.
• Five-sided transparent glass draft shield with sliding front door—designed for rapid access, full visual monitoring, and effective airflow isolation without compromising ergonomics.
• Integrated diagnostics suite including real-time overload detection, sensor saturation alert, and four-point linear calibration verification during startup.
• High-density PCB architecture featuring surface-mount components and dedicated analog signal conditioning circuitry to reduce noise coupling and improve ADC resolution fidelity.

Sample Compatibility & Compliance

The JA-C accommodates standard laboratory containers—including weighing boats, vials, crucibles, and beakers—within its 80 mm diameter stainless-steel weighing pan. The 240 mm vertical working clearance allows compatibility with tall sample vessels and standard volumetric flasks up to 1 L. While not certified for GLP/GMP-regulated production environments, the balance conforms to ISO 7709 (laboratory balance performance testing), ISO 9001 quality management system standards at the manufacturing level, and general-purpose accuracy class III per OIML R 76-1. Internal calibration traceability is maintained through factory-set reference weights; external recalibration using NIST-traceable standards is recommended annually or after relocation or environmental shock.

Software & Data Management

The JA-C operates as a standalone instrument with no embedded USB or RS-232 connectivity. Data output is limited to real-time display and manual transcription. For integration into validated workflows, users may employ third-party serial-to-USB adapters and compliant terminal emulation software (e.g., Tera Term, PuTTY) to capture stabilized weight values. Though lacking native 21 CFR Part 11 audit trail capabilities, the device supports basic data integrity practices when used in conjunction with laboratory notebooks or LIMS systems that enforce user authentication and timestamped entry protocols. Firmware updates are not field-upgradable; service-level revisions require authorized technical support intervention.

Applications

• Quality control checks for raw material batch verification in pharmaceutical excipient handling and dietary supplement manufacturing.
• Weighing of reagents and standards during HPLC, GC, and titration method development and execution.
• Preparation of calibration standards for spectroscopic and electrochemical instrumentation.
• Student laboratory instruction in analytical chemistry, food science, and materials engineering curricula.
• Inventory management and dispensing control in central stockrooms where sub-gram accuracy is required but regulatory validation is not mandated.

FAQ

What does “1 mg readability” mean in practice?
Readability refers to the smallest increment displayed—not necessarily the uncertainty. At 1 mg, the JA-C resolves mass changes down to 0.001 g; however, repeatability and linearity error remain ±1 mg under ISO 9001 test conditions.
Is the internal calibration traceable to national standards?
Internal calibration uses factory-programmed reference points derived from NIST-traceable master weights during production. Full traceability documentation requires external calibration with accredited standards.
Can this balance be used in a fume hood?
No. The five-sided glass shield is not rated for corrosive or solvent-laden atmospheres. Use only in well-ventilated, temperature-stable laboratory environments free of drafts and vibration sources.
Does the JA-C support piece counting or percentage weighing modes?
Yes—basic auxiliary functions include parts counting (with user-defined sample unit weight), percent weighing relative to a reference mass, and net/gross/tare toggling.
What maintenance is required beyond calibration?
Daily cleaning of the pan and shield with lint-free cloth and isopropyl alcohol; monthly inspection of leveling feet and environmental stability logs; annual verification by qualified metrology service provider.