ELECTROMAGNETIC COMPATIBILITY AND MEDICAL DEVICES - Design and Development of Medical Electronic Instrumentation - page 170

L1

Hot

50uH

(Black)

C3
0.1uF 600VAC

C1
1.0uF 400VAC

R1
1K

Phase Selection Switch

J1 J2

To
Device
Under
Test

1

1

Hot

To
Powerline

Ground

3 3

Neutral

(Green)

2 2

R2
1K

Neutral S SW DPDT

(White)

R3
50

C2
1.0uF 400VAC C4

0.1uF 600VAC

L2

50uH

J3 BNC

1

2

To 50 ohm
Spectrum
Analyzer

Permanent Connection
to Ground

Figure 4.16 A 50 Ω/50 µH LISN as defined by standard CISPR16-1. This circuit provides a 50-Ω output impedance for measurement of
RF emissions produced by the device under test. Conducted emission measurements are carried out from 150 kHz to 30 MHz.

To Spectrum Analyzer

SA 1 SA 2

H-Field
Probe

5 8

L3

Metal Box

Insulated Wire

1 4

HOT

HOT CB1 L1

500 uH

L4
50 uH

Black

Black

1 2

1

R1

C2
0.22uF 600 VAC

47

LA1
110V Neon Lamp Assy.

2

J1 R2

1 1

GROUND

GROUND

J2

Green

Green

3 3

C1
1uF 400VAC

C3
2uF 400 VAC

2 2

L2
500 uH

NEUTRAL NEUTRAL

White

White

120 V

Figure 4.17 A safer way of running lab tests is to use a LISN in which radiated emissions are coupled inductively to a spectrum analyzer.
L3 is a single loop of No. 14 stranded insulated wire which is coupled to an H-

fi eld probe made of a VCR head.

170