Extech Instruments 7630 Operation Manual page 70

MD5 EM0
MD6 EM3
MD7
External EM8
Frequency EM9
Check
Circuit Diagrams
The following diagrams show the equivalent circuit of the measuring devices. Leakage current
readings are generated by measuring the voltage drop across these networks and dividing by
the equivalent DC resistance. The voltmeter is placed across the entire network of the
measuring devices3、4、5、6 and 7. The voltmeter is placed across the points indicated by the
solid black dots on measuring device 1 and 2. The points are specified by the agencies that
require a particular measuring device to meet their specification.
MD 1： IEC60990(Fig 4 U1 & U2)、IEC60950-1、 IEC60598-1、 IEC60065、 IEC61010
MD2： IEC60990(Fig 5 U1 & U3) , IEC60598-1
1.5K
A
B
500
MD4：UL544P
64
UL544NP、UL484、UL923、UL471、
UL867、UL697
UL1563
IEC60950、IEC61010-1 Fig A.2 (2Kohm) Information Technology.
External
The Touch Current test can be configured to
verify the bandwidth of the leakage current
"voltmeter", by setting the Probe
configuration, Probe-HI to Probe-LO, and
selecting the medical device "Frequency
Check".
1.5KΩ
A
500Ω
B
0.22uF
10K
20K
U1 0.0091u
0.0062u
MD5： UL544NP、UL484、UL923、
UL471、UL867、UL697
Medical Equipment.
Electric Spas,
Equipment Assemblies and
Associated Equipment.
Laboratory Equipment.
(For Opt. 752)
External
The selection is intended to be used for
meter verification only and has no
application for normal testing.
0.22uF
10KΩ
U1
0.022uF
MD3： IEC60601-1
A
U3
B
MD6：UL1563
U2