What Is an ESD Simulator?
ESD simulators evaluate the discharge phenomenon commonly referred to as “static electricity,” or the electrical energy generated when charged particles or objects are discharged into electronic equipment. Static electricity testing is one of the most essential items in the EMC testing of IEC (International Electrotechnical Commission) standards for evaluating noise immunity, called ESD (electrostatic discharge) testing. The actual output voltage of the testing machine varies depending on the device, and we select a testing machine suitable for testing per various standards for each product.
Uses of ESD Simulators
In Japan, there are no specific standards for electrostatic discharge testing. However, the IEC international standard includes an “Immunity Test Method for Electrostatic Discharge,” and the European EMC standard EN55014-2 and EN61000-4-2 include electrostatic discharge testing as a test condition, making this test an essential item as an international standard.
The international standard for electrostatic testing classifies the degree to which equipment can withstand static electricity into multiple levels. In the case of contact discharge electrostatic testing, the first level is 2kV, the next is 4kV, the next is 6kV, and the next is 8kV. ESD simulators are used in these tests.
Principles of ESD Simulators
ESD simulators use a contact-type discharge method, which is different from the discharge of electricity charged on the human body in the atmosphere because it is a stable discharge.
In contact-type equipment, a high-voltage relay inside the ESD simulator’s gun is applied via a discharge resistor to a discharge electrode previously in contact with the ESD simulator using an electric charge from an energy-storing capacitor. Compared to the in-air discharge method, which discharges like fireworks in the air, this contact-type discharge is via a mechanical contact point using a high-voltage relay enclosed in inert gas at high pressure, enabling highly accurate discharges.
Currently, mainstream ESD simulators use the contact discharge method. The IEC standard specifies the current waveform to be applied at the time of discharge in contact-type discharges, which are highly reliable. The current waveform applied during discharge can be measured as a voltage drop (current) across a resistor using an oscilloscope or similar device, allowing measurement in compliance with the regulations by checking the waveform before testing.