AMPTEC Research · Failsafe Igniter Testers
620A-4R
Rugged, waterproof digital failsafe ohmmeter for igniter testing
The 620A-4R is the ruggedized version of the 620A-4. It keeps the same ultra-safe internal circuitry and adds a waterproof, weatherproof case and a wide-viewing angled display. It is made for resistance tests on bridgewires, squibs, flares and other explosive devices, and suits military and commercial crews who have to work in harsh conditions. Evencat is AMPTEC's sole distributor in Taiwan.
Overview
The AMPTEC 620A-4R is a rugged, waterproof, portable digital failsafe ohmmeter for resistance testing on bridgewires, squibs, flares and other explosive devices. It carries the 620A-4 circuit inside a weatherproof reinforced case, with an internal Faraday cage for noise immunity and a wide-viewing angled 4½ digit LED display. Four ranges of 20Ω, 200Ω, 2kΩ and 20kΩ run at nominal test currents of 5mA, 500µA, 50µA and 5µA, each with its own failsafe current limit, so the test current can never exceed the safe threshold. Accuracy is ±.02% of reading and range on every range. The meter is built under ISO 9001:2015, UL-913 compliant, and in service with NASA and the USAF. Before ordering, choose a probe or lead set and decide whether you need the OP-247 continuous power, OP-232 RS232C or OP-500 analog output options fitted at the factory. For defense, aerospace and ordnance sites, the 620A-4R is a practical choice for firing-circuit verification.
Key specifications
| Ranges | 20Ω / 200Ω / 2kΩ / 20kΩ |
|---|---|
| Nominal test current | 5mA / 500µA / 50µA / 5µA |
| Failsafe current | 8mA / 1.5mA / 150µA / 15µA |
| Resolution | 1mΩ / 10mΩ / 100mΩ / 1Ω |
| Accuracy | ±.02% of reading & range |
| Display | 4½ digit LED |
| Open circuit voltage | 1.6 VDC |
| Max input voltage | 250 VDC |
| Max internal voltage | 15 VDC |
| Update rate | 3 readings/second |
| Operating temperature | 0° to 50°C |
| Power | 4 rechargeable 5AHr NICAD batteries |
Features
Failsafe test current
The test current on every range is failsafe-limited (8mA / 1.5mA / 150µA / 15µA), so it can never pass the safe threshold on bridgewires, squibs and other explosive devices.
Waterproof weatherproof reinforced case
The 620A-4 ultra-safe circuit in a waterproof, weatherproof rugged housing, for hard military and outdoor field work.
Internal Faraday cage for noise immunity
The built-in Faraday cage isolates electrical noise, so resistance readings stay stable and repeatable in electrically noisy surroundings.
Wide-viewing angled LED display
A wide-viewing angled 4½ digit LED display and ±.02% of reading and range accuracy make readings easy to see and easy to trust.
Certified and trusted
Built under ISO 9001:2015, UL-913 compliant, and in service with NASA and the USAF.
Typical applications
Aerospace and defense
Field acceptance testing of rocket and missile firing circuits
Outdoors at a missile maintenance base or launch site, ground engineers use the 620A-4R to measure the resistance of igniter bridgewires (EBW) and pyrotechnic circuits and clear them for the next step only when the value is in spec. The weatherproof case and internal Faraday cage keep site electromagnetic noise out, so readings stay stable in bad weather and high interference.
Space missions
Pyrotechnic safety confirmation on NASA and USAF space vehicles
In service with NASA and the US Air Force, the 620A-4R verifies continuity and resistance of pyrotechnic initiators (squibs) in space vehicle propulsion systems before installation. The maximum test current is held below 8mA so sensitive pyrotechnics cannot fire, and the four ranges (20Ω to 20kΩ at ±0.02% accuracy) cover bridgewires of different ratings to meet strict pre-mission quality requirements.
Defense manufacturing
Quality control on military munitions production lines
In an ammunition plant or a field repair shop, the 620A-4R's weatherproof reinforced case and internal Faraday cage keep it working through the heat, humidity and vibration of a production line, serving as the final electrical check on igniter circuits before shipment. Compared with an ordinary bench ohmmeter, its UL-913 compliance and failsafe current protection greatly reduce the risk of accidental initiation for staff working in hazardous areas.
Options and configuration
Tick the options you need; we will assemble the configuration list and carry it into the inquiry form.
Standard equipment (included)
Hardware options / factory modifications
Optional accessories
Downloads
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