What Is CISPR 32? Emission Testing for Multimedia Equipment
The scope of CISPR 32, the emission standard for computers, displays, printers and AV equipment, its Class A and B limits and the test setup.
3 min readOctober 11, 2026
What Is ESD and Why Test It?
A person walking across a carpet can build up a static charge of several thousand volts. When they touch a device, the charge discharges in a very short time and a high-current pulse appears in the circuit. The result is sometimes just a screen flicker, sometimes permanent damage.
IEC 61000-4-2 measures a device's immunity with an ESD gun that reproduces this event repeatably in the lab. This test is part of the CE process for almost every electronic product.
Contact and Air Discharge
In contact discharge, the gun tip touches a conductive surface of the device and the discharge is triggered. In air discharge, the charged tip approaches insulating surfaces such as plastic and the spark jumps through the air. The two methods have different levels.
Typical test levels are 4 kV for contact and 8 kV for air; some product standards require more. The test is applied to every point a user can touch and to nearby horizontal and vertical coupling planes.
The Test Environment
ESD testing doesn't need a shielded room, but it does need a controlled setup: a grounded reference plane, an insulating table and defined distances. Humidity also affects the result, so ambient conditions are recorded.
That's why many labs run ESD tests on a separate bench next to the area where emission and immunity tests are performed. Setting up the same arrangement in-house for pre-testing is very economical.
Where Do Products Most Often Fail?
The most common problem spots are around connectors, metal screws, keypads and plastic housing joints. If the discharge current finds a short path into the circuit, the microcontroller resets or data is corrupted.
The fix is usually TVS diodes on the board, a proper ground path and small changes to the housing design. Making these corrections early in the design is the biggest gain of a pre-test approach.
Frequently Asked Questions
Does ESD testing need an anechoic chamber?
No. ESD testing is done on a bench set up per the standard; an anechoic chamber is needed for emission and radiated immunity tests.
Does the device shutting down mean a fail?
It depends on the performance criterion in the product standard. For some products a temporary interruption is accepted if the device recovers on its own.
How many points are discharged?
Every point a user can reach is tested, with at least ten discharges at each point in both positive and negative polarity.
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