1. Overview of Conducted Emissions

Conducted emissions are also commonly referred to as disturbance voltage tests. Any product with a power cord involves conducted emissions testing, including many DC-powered products. Additionally, many standards also have requirements for conducted emissions on signal/control lines, typically expressed in terms of disturbance voltage or current limits (the two are convertible). Insertion loss testing (expressed directly in dB) for lighting fixtures also falls under the category of conducted testing.

2. Conducted Emissions Test Frequency Range:

Most are 150kHz-30MHz, with CISPR15 being an exception (disturbance voltage 9kHz-30MHz, insertion loss 150kHz-1,605kHz).

3. Conducted Emissions Test Methods:

1) Conducted Emissions Test Setup: Divided into table-top and floor-standing. Table-top equipment is placed 80cm from the LISN and 40cm from the ground plane (which can be a horizontal ground plane or the vertical inner wall of the shielded room). For floor-standing equipment, the distance from the ground plane varies with different standards: CISPR 14-1, 15 allow 10cm +/- 25%; CISPR 13 allows up to 12mm; CISPR 22 allows up to 15cm; CISPR 11 does not specify a distance but requires insulation from the ground plane. The arrangement of auxiliary equipment also varies with the test standard. In CISPR 22, auxiliary equipment is placed 10cm from the main device, and interconnection cables must be at least 40cm from the ground plane. Hand-held Class II equipment requires a simulated hand. In CISPR 15, self-ballasted fluorescent lamps need to be covered with an auxiliary conical metal shield.

2) Conducted Emissions Test Frequency Range: Most are 150kHz-30MHz, with CISPR15 being an exception (disturbance voltage 9kHz-30MHz, insertion loss 150kHz-1,605kHz).

3) Conducted Emissions Test Limits:

Limits vary depending on different standards and product classifications (Group 1/2, Class A/B).

4. Conducted Emissions Test Result Evaluation:

This is straightforward. The measured values (QP/AV) from the receiver detector are compared with the limit lines. Below the limit line is PASS; above is FAIL.

5. Notes for Conducted Emissions Testing:

Since conducted testing measures common-mode disturbances relative to ground, the key lies in the test setup. Once the setup is correct, measurements with a receiver are straightforward. Variations in the setup can lead to discrepancies in results.