Guance GEST-121A Automated Insulation Resistivity Tester
| Brand | Guance Instruments |
|---|---|
| Origin | Beijing, China |
| Manufacturer Type | Authorized Distributor |
| Country of Origin | China |
| Model | GEST-121A |
| Price | USD 410 (FOB) |
Overview
The Guance GEST-121A Automated Insulation Resistivity Tester is a precision digital instrument engineered for high-accuracy measurement of insulation resistance, volume resistivity, and surface resistivity in dielectric materials. Based on the constant-voltage direct-current (DC) method per ASTM D257 and IEC 60093, the system applies programmable test voltages (10 V to 1000 V DC) across standardized electrode configurations to quantify electrical resistance over an extended dynamic range—from 1 × 10⁴ Ω up to 2 × 10¹⁶ Ω—with resolution down to 0.01 MΩ. Its core architecture integrates a low-noise, high-input-impedance amplifier stage and a proprietary analog-to-digital conversion circuit built around Intel® large-scale integrated circuits, ensuring thermal stability, minimal drift (<0.1% per hour), and repeatability within ±1% of reading across its full scale. Designed for laboratory and QC environments, the GEST-121A delivers traceable, GLP-compliant resistivity data without manual recalibration between measurements.
Key Features
- Automated dual-mode measurement: simultaneous acquisition of volume resistivity (ρᵥ, in Ω·cm) and surface resistivity (ρₛ, in Ω/sq) with automatic electrode configuration recognition
- Programmable DC test voltage output: 10 V, 100 V, 250 V, 500 V, and 1000 V—each selectable via front-panel interface or remote command
- Integrated microcurrent detection: measures currents from 1 fA to 1.999 mA with <10 fA noise floor, enabling reliable evaluation of ultra-low-conductivity polymers and ceramics
- Self-calibrating reference circuitry: maintains accuracy across temperature variations (15–30 °C operational range) and humidity fluctuations (30–70% RH, non-condensing)
- Compact benchtop form factor (280 × 220 × 120 mm), lightweight chassis (<3.2 kg), and EMI-shielded enclosure compliant with EN 61326-1 for electromagnetic compatibility
- Front-panel LCD with real-time display of resistance value, current reading, elapsed test time, and pass/fail status relative to user-defined limits
Sample Compatibility & Compliance
The GEST-121A supports a broad spectrum of insulating sample geometries—including rigid solids (e.g., molded plastic plaques, ceramic substrates), flexible films (≥25 µm thickness), granular powders (in compression cells), viscous pastes (in guarded cup electrodes), and low-conductivity liquids (using concentric cylindrical cells). It is compatible with standard ASTM D257-compliant electrode sets: two-terminal collinear probes for bulk resistivity; three-terminal guarded ring electrodes for surface resistivity isolation; and liquid immersion cells per ASTM D1169. All measurements adhere to ISO/IEC 17025 technical requirements for calibration traceability, and raw data meet FDA 21 CFR Part 11 audit-trail readiness when exported via USB to external storage.
Software & Data Management
While the GEST-121A operates as a standalone instrument, it includes a USB 2.0 interface supporting ASCII-formatted data export (CSV-compatible) for post-processing in Excel, MATLAB, or LIMS platforms. Optional PC software (v3.2, Windows 10/11 compatible) enables automated test sequencing, multi-sample batch logging, statistical analysis (mean, SD, CV%), and report generation conforming to internal QA templates or ISO 9001 documentation standards. All stored records retain timestamp, operator ID, environmental conditions (manually entered), and instrument serial number—supporting full GLP/GMP audit readiness.
Applications
- Quality control of polymer insulators in wire & cable manufacturing (e.g., PE, XLPE, ETFE)
- Evaluation of anti-static additives in packaging films and cleanroom garments
- Resistivity mapping of printed electronics substrates (PET, PI) prior to metallization
- Characterization of ceramic green tapes and sintered dielectrics for capacitor development
- Stability testing of battery separator membranes under accelerated aging protocols
- Validation of conformal coatings on PCB assemblies per IPC-CC-830B
FAQ
What voltage ranges are supported for resistivity testing?
The GEST-121A provides five fixed DC test voltages: 10 V, 100 V, 250 V, 500 V, and 1000 V—selected manually or via software command.
Does the instrument include calibration certificates?
Yes—each unit ships with a factory calibration certificate traceable to NIM (National Institute of Metrology, China), valid for 12 months under normal use conditions.
Can it measure resistivity of conductive liquids like transformer oil?
Yes—when used with the optional ASTM D1169-compliant liquid cell and appropriate guard configuration, it measures volume resistivity of hydrocarbon-based insulating oils per IEC 60296.
Is the GEST-121A suitable for ISO 17025-accredited laboratories?
Yes—its documented measurement uncertainty budget, stable reference design, and full data logging capability satisfy key technical requirements for accredited testing of electrical insulation properties.
How often does the instrument require recalibration?
Annual recalibration is recommended; however, built-in self-test diagnostics and reference resistor verification allow daily operational checks without external equipment.
