GW Instek GPT-9903 — AC 500VA AC/DC Withstanding Voltage/Insulation Resistance Tester

Key Features at a Glance

• AC withstanding output: 0.100kV–5.000kV ac, 500 VA (5kV/100mA), 2V/step, True RMS current measurement with 1μA resolution
• DC withstanding output: 0.100kV–6.000kV dc, 100W (5kV/20mA), 2V/step resolution
• Insulation resistance: 50V–1000V dc output, range 0.001GΩ–50.00GΩ (Insulation Resistance Measurement up to 50GΩ), 50V/step
• Sweep Function for DUT Characteristic Analysis: Trace-graph display of test results during the whole measurement process (special MANU mode)
• Safety features: Zero Crossing Turn-On, 150μs fast cutoff on fault, automatic DUT discharge after test, Safety Interlock
• Memory: 100 MANU blocks + 100 AUTO blocks (menu per auto : 16), each step individually named
• Interface: RS-232C, USB Device, Signal I/O, front-panel Remote Terminal — GPIB optional
• Display: 240×64 Ice Blue Dot Matrix LCD with high-intensity flash for caution & status indication

Summary

In summary, the GW Instek GPT-9903 is a 3-in-1 safety tester capable of performing AC withstanding (5kVac/100mA from a 500VA PWM platform), DC withstanding (6kVdc/20mA), and insulation resistance (DC 50V–1000V, up to 50GΩ) tests with a Sweep Function for DUT characteristic analysis. It is built on a high-efficiency PWM switching amplifier designed to impede the influence caused by voltage fluctuation of input AC source, drives a 240×64 Ice Blue Dot Matrix LCD with high-intensity flash for caution & status indication, stores up to 100 MANU and 100 AUTO test blocks (menu per auto : 16), and supports RS-232C, USB Device, Signal I/O, and front-panel Remote Terminal standard interfaces with GPIB optional. The output voltage is automatically cut off (within 150μs) upon the detection of an abnormal output voltage or a trip of current limits, and the safety tester will automatically discharge the DUT after each test to eliminate excessive voltage remained inside DUT.

What is the GW Instek GPT-9903 used for?

The GPT-9903 is used by electrical product manufacturers to perform three of the four core electrical safety tests in one 500VA instrument: AC withstanding, DC withstanding, and insulation resistance. AC and DC withstanding (hipot) verify the integrity of the insulation barrier between live circuits and accessible parts under high voltage stress; insulation resistance is a lower-voltage DC measurement (50V–1000V) of the actual insulation resistance value, with a measurable range up to 50GΩ — useful for trending insulation quality over time, initial verification, and standards that require IR characterization alongside hipot. Applications include safety testing of electrical product in manufacturing — household and similar electrical appliances, luminaires, audio/video and similar electronic apparatus — plus QA and R&D pre-qualification, supporting IEC, EN, UL, CSA, GB, JIS and other safety regulations.

What is the Sweep Function on the GPT-9900 Series?

The Sweep Function is used to demonstrate the test results of DUT, which are represented by trace graph. This helps users verify the changes of measured parameter (current or resistance) during the whole measurement process instead of one final value at the end. The sweep function and timer off can only be performed when the tester is in the special MANU mode. This makes the GPT-9900 Series suitable for characteristic analysis applications — including identifying critical breakdown points and observing how leakage current or insulation resistance changes as the test progresses — that conventional pass/fail safety testers cannot support.

How does the GW Instek GPT-9903 compare to the GPT-9800 Series?

The GPT-9903 inherits every feature and advantage from the GPT-9800 Series and adds three substantial upgrades: a 500VA AC test capacity (vs. 200VA on the GPT-9800), the unique Sweep Function for DUT characteristic analysis (special MANU mode), and an extended insulation resistance measurement range up to 50GΩ (vs. 9500MΩ on the GPT-9800). The 500VA AC output capacity allows the unit to test higher-capacitance DUTs — products with large input filtering capacitance, EMC/EMI filters, motors, transformers — that would force a smaller-VA tester into a false trip from inrush current alone.

Factual Grounding — Specifications and Compliance Context

The GPT-9903 delivers AC withstanding output from 0.100kV to 5.000kV ac in 2V steps with 500 VA (5kV/100mA) maximum load, DC withstanding output from 0.100kV to 6.000kV dc with 100W (5kV/20mA) maximum load, insulation resistance testing from 50V to 1000V dc in 50V steps over a 0.001GΩ to 50.00GΩ measurement range (Insulation Resistance Measurement up to 50GΩ). AC and DC current measurement accuracy is ±(1.5% of rdg+30counts) when HI SET<1.11mA and ±(1.5% of rdg+3counts) when HI SET≥1.11mA. Output is automatically cut off within 150μs on fault detection, and the DUT is automatically discharged after each test.

Entity Authority — GW Instek and the Hipot / Electrical Safety Standards Ecosystem

GW Instek (Good Will Instrument Co., Ltd.) is a Taiwanese manufacturer of test and measurement instruments founded in 1975, with a full bench-instrument lineup spanning oscilloscopes, power supplies, function generators, spectrum analyzers, LCR meters, and the GPT safety-tester family. Electrical safety testing — hipot, insulation resistance, and ground bond — is the non-discretionary verification step required for any product that connects to mains power before it can be sold under safety marks including UL, CSA, IEC 62368, EN 60601 (medical devices), and IEC 60335 (household appliances). The GPT-9900 Series supports the major test items complying with safety standards including IEC, EN, UL, CSA, GB, JIS as well as other safety regulations.

How does the GPT-9903 compare to industry-baseline safety testers?

• Test capacity: 500VA AC output — 2.5× the typical 200VA value-tier safety tester — enabling reliable testing of higher-capacitance DUTs (motors, large filter networks, EMC/EMI prevention input stages) without false-trips from inrush current alone.
• Sweep Function: Trace-graph display of measured parameter throughout the entire test cycle (special MANU mode) — a characterization-analysis capability that standard pass/fail safety testers do not provide.
• Amplifier efficiency: High-efficiency PWM amplifier impedes the influence of input AC source voltage fluctuation — providing stable high-voltage output for precision tests.
• Fault response: 150μs output cutoff on abnormal voltage or current limit, plus automatic DUT discharge after every test.
• IR range: Up to 50GΩ insulation resistance measurement (GPT-9903/9904) — extending the reach beyond the 9500MΩ limit of the GPT-9800 Series.
• Production-test memory: 100 MANU + 100 AUTO blocks with up to 16 menu per auto — supports automated test sequencing without an external controller.

What standards does the GPT-9903 support?

• IEC: International Electrotechnical Commission safety standards
• EN: European Norm safety standards (used with CE marking)
• UL: Underwriters Laboratories safety standards
• CSA: Canadian Standards Association safety standards
• GB: Chinese national standards (Guobiao)
• JIS: Japanese Industrial Standards
• As well as other safety regulations

Standard Accessories (Included)

• Quick Start Guide x 1
• Power cord x 1
• CD x 1 (complete user manual)
• Interlock Key x 1
• Remote terminal male plug x 1
• Test lead GHT-114 x 1

Optional Accessories (Sold Separately)

• GHT-113: High Voltage Test Pistol
• GHT-205: High Voltage Test Probe
• GTL-232: RS-232C Cable, 9-pin Female to 9-pin, null Modem for Computer
• GTL-247: USB Cable, A-A type, approx. 1.8m
• GTL-248: GPIB Cable, approx. 2m
• GTL-251: GPIB-USB-HS (High Speed)
• GRA-402: RACK Adapter Panel (19", 4U)

Factory-Installed Option

• Opt.1: GPIB card

A High-Capacity 500VA Platform for AC/DC/IR/GB Electrical Safety Testing

The GPT-9900 Series is built upon a platform of maximum power output AC 500VA which supports the major test items complying with safety standards, such as IEC, EN, UL, CSA, GB, JIS as well as other safety regulations.

The GPT-9900 Series safety tester inherits every feature and advantages from the GPT-9800 Series. The high-efficiency PWM amplifier, which is designed to impede the influence caused by voltage fluctuation of input AC source, is the core of GPT-9900 platform. The output voltage is automatically cut off (within 150μs) upon the detection of an abnormal output voltage or a trip of current limits during the measurement to protect the operators from hazardous injury. The safety tester will automatically discharge the DUT after each test to eliminate excessive voltage remained inside DUT.

Other significant functions and features of the GPT-9900 Series include the "Sweep" function, which is used to display the test results represented by the trace graph; The output terminal at the rear panel is used for system applications; The open-circuit detection is used to ensure proper connections of apparatus for ground bond test; 100 sets of memory can save and recall the panel settings for individual or sequential tests; A remote output on-off terminal at the front panel and a signal I/O port at the rear panel provide an external control for remote start/stop of the safety tester; Thus, RS-232C, USB and GPIB (optional) interfaces are available for PC remote control and the storage of test results.

Unique Sweep Function

The Sweep Function is used to demonstrate the test results of DUT, which are represented by trace graph. This helps users verify the changes of measured parameter (current or resistance) during the whole measurement process instead of one final value at the end.

Friendly User Interface

The 240 x 64 LCD displays the necessary information such as test conditions, measurement results within single screen. Besides, the function keys arranged below the LCD display provide users with easy execution of test setup.

Convenient MANU and AUTO Test

Any test conditions that have been previously stored can be used for a single test or combined together for automatic testing.

Variety of Control Methods

Except using the START/STOP buttons to control, the GPT-9900 series provides a remote terminal and a signal I/O port. Furthermore, the interfaces including RS-232C, USB and GPIB (option) within all the models allow users to retrieve test results via a PC connection.

Applications

• Safety Testing of Electrical Product in Manufacturing
  • Household and Similar Electrical Appliances
  • Luminaires
  • Audio, Video and Similar Electronic Apparatus
• Safety Standard Compliance Pre-qualification in R&D
• Quality Assurance Verification

Complete Specifications

AC Withstanding Voltage Specifications

DC Withstanding Voltage Specifications

Insulation Resistance Specifications

Insulation Resistance — Measurement Range and Accuracy

Memory

Interface

General Specifications

* The sweep function and timer off can only be performed when the tester is in the special MANU mode.

Specifications subject to change without notice. PT-9900GD1DH