Yoke PHS-3C Benchtop Digital pH Meter
| Brand | Yoke |
|---|---|
| Origin | Shanghai, China |
| Manufacturer Type | Direct Manufacturer |
| Instrument Type | Benchtop |
| Parameter Type | Single-Parameter (pH/mV) |
| Measurement Range | 0.0–14.0 pH |
| Resolution | 0.1 pH |
| Accuracy | ±0.1 pH |
| Temperature Compensation | Manual (0–60 °C) |
| Display | 3½-digit LED |
| Input Impedance | ≥1×10¹² Ω |
| Stability | ±0.1 pH / 3 h |
| Calibration | One-point or two-point using standard buffer solutions (Chinese national buffer series) |
| Included Accessories | E-201-C combination pH electrode, two sets of pH calibration buffer powders |
Overview
The Yoke PHS-3C Benchtop Digital pH Meter is a precision electrochemical instrument engineered for reliable, repeatable measurement of hydrogen ion activity in aqueous solutions—expressed as pH—and direct electromotive force (EMF) in millivolts (mV). Operating on the fundamental Nernst principle, the meter detects potential differences between a pH-sensitive glass membrane and a stable reference electrode, converting the resulting voltage into a calibrated pH reading. Designed for routine quality control, teaching laboratories, and industrial process support, the PHS-3C delivers consistent performance under standard ambient conditions without requiring complex setup or software integration. Its fully integrated temperature-compensated design accommodates manual thermal correction across a 0–60 °C range, ensuring measurement integrity when solution temperature deviates from 25 °C—the reference point for most pH buffer standards. The instrument conforms to GB/T 11165–2005 (Chinese national standard for laboratory pH meters), aligning with internationally recognized metrological practices for Class 0.1 accuracy instruments.
Key Features
- 3½-digit LED display with high-contrast numeric readout for clear visibility under varied lighting conditions
- Manual temperature compensation via front-panel adjustment knob, enabling real-time correction without external probes
- Dual-mode operation: simultaneous selection between pH and mV measurement modes using dedicated toggle switches
- High-input-impedance circuitry (≥1×10¹² Ω) minimizes loading effects on high-resistance pH electrodes, preserving signal fidelity
- Robust benchtop architecture with compact footprint (300 × 220 × 90 mm) and lightweight aluminum chassis (1.3 kg)
- Factory-calibrated E-201-C combination pH electrode included—designed for rapid response, low drift, and compatibility with common aqueous samples
- Two-point or single-point calibration capability using standardized Chinese national buffer solutions (pH 4.01, 6.86, and 9.18 at 25 °C)
Sample Compatibility & Compliance
The PHS-3C is optimized for aqueous, low-ionic-strength solutions typical in educational labs, water treatment facilities, food processing QC, and basic chemical synthesis workflows. It is not intended for non-aqueous solvents, highly viscous media, or aggressive oxidizing/reducing environments where electrode poisoning may occur. All electrical interfaces comply with IEC 61010-1 safety requirements for laboratory electrical equipment. While not certified to ISO/IEC 17025 or GLP/GMP out-of-the-box, the instrument supports traceable calibration documentation when used with NIST-traceable buffer standards and maintained per manufacturer-recommended procedures. Its manual temperature compensation method satisfies basic ASTM D1293 and ISO 10523 compliance pathways for field and lab pH reporting where automated sensing is not mandated.
Software & Data Management
The PHS-3C operates as a standalone analog-digital hybrid instrument with no embedded microprocessor-based data logging or PC connectivity. All measurements are displayed in real time; no internal memory or export functionality is provided. This design prioritizes operational simplicity, electromagnetic noise immunity, and long-term reliability in environments where networked instrumentation introduces unnecessary complexity or cybersecurity exposure. Users seeking audit-ready records must manually transcribe readings or integrate the unit into external data acquisition systems via its analog mV output (if externally enabled through optional interface modules—not supplied with base configuration). For regulated environments requiring electronic record integrity, supplementary validation documentation (e.g., IQ/OQ protocols) must be developed by end users per FDA 21 CFR Part 11 guidelines if connected to compliant data capture hardware.
Applications
- Academic instruction in general chemistry, environmental science, and analytical methodology courses
- Routine monitoring of potable water, wastewater effluent, and aquarium system pH stability
- Quality assurance testing of cleaning agents, disinfectants, and personal care formulations
- Soil extract analysis (saturated paste method) following APHA Standard Methods 4500-H⁺ B
- Calibration verification of higher-tier pH meters and electrode performance screening
- Basic fermentation broth monitoring during small-scale bioprocess development
FAQ
Does the PHS-3C support automatic temperature compensation (ATC)?
No—temperature compensation is strictly manual. Users must measure sample temperature separately and adjust the compensation dial accordingly.
Can the PHS-3C measure pH values outside the 0.0–14.0 range?
No. The instrument’s analog front-end and calibration algorithm are validated only within the specified 0.0–14.0 pH span.
Is the included E-201-C electrode compatible with ISO-standard buffers?
Yes—when reconstituted per instructions, the supplied Chinese national buffer powders align closely with ISO 3696 Grade 3 water and exhibit ≤±0.02 pH deviation from NIST SRM 186, provided storage and handling follow GB/T 27404 guidelines.
What maintenance is required to sustain ±0.1 pH accuracy?
Electrode hydration (storage in 3 M KCl solution), regular cleaning with mild detergent or dilute HCl, and periodic recalibration against fresh buffer standards are essential. Avoid prolonged dry storage or contact with strong solvents.
Is technical support available in English for international customers?
Yes—Yoke provides English-language operation manuals, calibration guides, and email-based engineering support for OEM and institutional purchasers. Firmware updates are not applicable, as the device contains no programmable logic.
