EMP/HEMP filters to protect critical equipment

EMP/HEMP filters to protect critical equipment

EMP/HEMP filters ensure critical electronic equipment survival during hazardous transient conditions

Available from APC Hi-Rel, API Technologies’ EMP/HEMP filters are designed to protect sensitive equipment during hazardous conditions by absorbing a potentially destructive overshoot voltage.

Under normal operating conditions, the suppressor circuit exhibits high off-state impedance that appears transparent to the circuits they protect. If a voltage exceeding the switching voltage is applied to the circuit, the suppressor circuit switches to very low impedance effectively shorting out the high voltage. The suppressor circuit will remain in the low impedance state until the current flowing through the suppressor is either interrupted or drops to a safe level. Once this occurs, the suppressor resets and returns to a high off-state impedance. These High Voltage HEMP Filters will also help meet the requirements of MIL-STD-188-125.

Learn more about naturally occurring EMI sources and dangers that include lightning and geomagnetic storms, and artificial EMI including electromagnetic pulse (EMP) and high-altitude electromagnetic pulse (HEMP) from the video below.

APC Technology Group plc

Power Filters

Available from APC Hi-Rel, APCI’s high voltage high-altitude electromagnetic pulse (HEMP) filters are designed to protect sensitive electronics equipment during hazardous transient conditions. Applications include commercial and industrial infrastructure, ground-based applications, radars, power grids and airborne communication systems.


  • Insulation resistance, DWV tested prior to discharge resistor and MOV installation
  • Temperature rise is less than 25°C
  • Filters rated for 6A, 16A, and 30A, additionally meet modified E3 pulse test
  • Meets Mil-STD-188-125, E1 and E2 pulse requirements
  • Custom designs available

To discuss our range of EMP/HEMP power filters

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