GuanCe GEST-121A4 Digital Ultra-High Resistance & Resistivity Tester
| Brand | GuanCe Instruments |
|---|---|
| Origin | Beijing, China |
| Manufacturer Type | Authorized Distributor |
| Country of Origin | China |
| Model | GEST-121A4 |
| Price | USD 1,700 (FOB Beijing) |
Overview
The GuanCe GEST-121A4 Digital Ultra-High Resistance & Resistivity Tester is an engineered solution for precise measurement of electrical insulation properties in solid, liquid, powder, and semi-solid dielectric materials. Based on the constant-voltage direct-current (DC) method per IEC 62631-3-1, ASTM D257, and GB/T 1410, the instrument determines volume resistivity (ρv, in Ω·m), surface resistivity (ρs, in Ω/sq), and insulation resistance (R, in Ω) across a wide dynamic range. Its core architecture integrates a low-noise, high-stability DC voltage source (10 V to 1000 V, selectable in 10-V increments), precision electrometer-grade current sensing circuitry, and auto-ranging feedback control—enabling reliable quantification of currents from 1 fA to 19.99 mA with <±1% reading uncertainty at mid-scale. Designed for laboratory-based quality control, R&D validation, and compliance testing, the GEST-121A4 supports traceable, repeatable characterization of insulating performance under standardized environmental conditions (23 °C ±2 °C, 50% RH ±5%).
Key Features
- Ultra-wide resistance measurement range: 1 × 104 Ω to 2 × 1018 Ω — covering low-conductivity polymers, ceramic substrates, epoxy encapsulants, and high-purity elastomers.
- Dual-mode operation: Simultaneous display of resistance value (Ω), resistivity (Ω·m or Ω/sq), and leakage current (A) with real-time auto-scaling.
- Integrated programmable DC voltage source: Adjustable output from 10 V to 1000 V in 10-V steps; regulated stability ≤0.1% over 1 hour.
- Intel-based embedded controller: Enables deterministic timing control for standardized dwell periods (e.g., 60-s ASTM D257 measurement interval), automatic guard terminal activation, and zero-current compensation.
- Modular electrode interface: Supports standardized three-terminal configurations including guarded two-electrode, concentric ring, and parallel plate electrodes per IEC 60243-1 and ASTM D257 Annex A3.
- Robust front-panel interface with backlit LCD, tactile membrane keys, and dedicated function shortcuts for rapid test setup and data recall.
Sample Compatibility & Compliance
The GEST-121A4 accommodates diverse physical forms without modification to core electronics: rigid solids (e.g., molded PVC, silicone rubber sheets), flexible films (<500 µm thickness), granular powders (in compression cells), viscous pastes, and low-conductivity liquids (e.g., transformer oil, silicone fluids). All measurements comply with internationally recognized test standards—including IEC 62631-3-1 (2016), ASTM D257-14 (Standard Test Methods for DC Resistance or Conductance of Insulating Materials), GB/T 1410-2006 (Chinese national standard equivalent), and ISO 3915. The system meets electromagnetic compatibility (EMC) requirements per IEC 61326-1 for laboratory environments and supports GLP-compliant documentation when used with external PC logging.
Software & Data Management
While the GEST-121A4 operates as a standalone instrument, it features an RS-232 serial interface (standard) and optional USB-to-serial adapter for bidirectional communication with Windows-based host software. This enables automated test sequencing, timestamped data export (CSV/Excel), statistical analysis (mean, SD, CV%), and report generation aligned with internal QA templates. Audit trails include operator ID, date/time stamp, applied voltage, dwell time, ambient temperature/humidity (when interfaced with external sensors), and raw current/resistance readings. Data integrity conforms to FDA 21 CFR Part 11 principles when deployed with validated software and user access controls.
Applications
- Quality assurance of polymer insulators in cable manufacturing and automotive wiring harnesses.
- Resistivity mapping of printed circuit board (PCB) substrate materials (FR-4, polyimide) during incoming inspection.
- Evaluation of anti-static additives in packaging films and cleanroom garments.
- Research into charge dissipation mechanisms in nanocomposite dielectrics (e.g., CNT-filled EPDM).
- Validation of moisture barrier integrity in pharmaceutical blister packaging using surface resistivity trends.
- Baseline characterization of ceramic insulators and high-voltage bushings prior to accelerated aging studies.
FAQ
What is the recommended calibration frequency for the GEST-121A4?
Annual calibration against NIST-traceable high-resistance standards (e.g., Keysight A9903A) is advised; interim verification using certified reference resistors (109 Ω to 1014 Ω) is recommended before critical test batches.
Can the instrument measure resistivity of conductive liquids such as electrolytes?
No—the GEST-121A4 is optimized for insulating and semi-insulating media (ρ > 106 Ω·m); conductive solutions require a four-point probe or AC impedance method.
Is guarding functionality available for surface resistivity measurements?
Yes—built-in guard terminal support enables compliant implementation of ASTM D257 Figure A3.3 (concentric ring electrode configuration) to eliminate edge leakage errors.
Does the unit include electrodes?
A basic set of parallel-plate electrodes (25 mm diameter) is supplied; specialized fixtures (e.g., volume resistivity cells, powder compaction dies) are available as optional accessories.
How does the instrument handle electrostatic interference in low-current measurements?
The chassis is fully shielded, input terminals use guarded triaxial connections, and firmware implements digital averaging over ≥10 measurement cycles to suppress broadband noise.
