KMP_786JC_A03 Page 4 of 4
786J Series
Surface Mount General Purpose Pulse Transformers
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Murata Power Solutions, Inc. makes no representation that the use of its products in the circuits described herein, or the use of other
technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not imply
the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without
notice. © 2012 Murata Power Solutions, Inc.
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A.
ISO 9001 and 14001 REGISTERED
TUBE OUTLINE DIMENSIONS
0.60±0.15
(0.023±0.005)
4.00 (0.16)
5.50 (0.22)
10.95
(0.43)
12.95
(0.51)
3.80
(0.15)
15.70 (0.62)
Tube length: 465±2 (18.3±0.08). Tube quantity: 50.
Tube material: Antistatic coated clear pvc.
Unless otherwise stated all dimensions in mm (inches) ±0.25 (0.01).
TECHNICAL NOTES
ISOLATION VOLTAGE
‘Hi Pot Test’, ‘Flash Tested’, ‘Withstand Volt-
age’, ‘Proof Voltage’, ‘Dielectric Withstand
Voltage’ & ‘Isolation Test Voltage’ are all terms
that relate to the same thing, a test voltage,
applied for a specified time, across a compo-
nent designed to provide electrical isolation, to
verify the integrity of that isolation.
All products in this series are 100% production
tested at their stated isolation voltage.
A question commonly asked is, “What is the
continuous voltage that can be applied across
the part in normal operation?”
For a part holding no specific agency approv-
als both input and output should normally be
maintained within SELV limits i.e. less than
42.4V peak, or 60VDC. The isolation test
voltage represents a measure of immunity to
transient voltages and the part should never
be used as an element of a safety isolation
system. The part could be expected to function
correctly with several hundred volts offset
applied continuously across the isolation bar-
rier; but then the circuitry on both sides of the
barrier must be regarded as operating at an
unsafe voltage and further isolation/insulation
systems must form a barrier between these
circuits and any user-accessible circuitry ac-
cording to safety standard requirements.
REPEATED HIGH-VOLTAGE
ISOLATION TESTING
It is well known that repeated high-voltage
isolation testing of a barrier component can
actually degrade isolation capability, to a
lesser or greater degree depending on ma-
terials, construction and environment. This
series has toroidal isolation transformers,
with no additional insulation between pri-
mary and secondary windings of enameled
wire. While parts can be expected to with-
stand several times the stated test voltage,
the isolation capability does depend on the
wire insulation. Any material, including this
enamel (typically polyurethane) is suscep-
tible to eventual chemical degradation when
subject to very high applied voltages thus
implying that the number of tests should be
strictly limited. We therefore strongly advise
against repeated high voltage isolation test-
ing, but if it is absolutely required, that the
voltage be reduced by 20% from specified
test voltage.
This consideration equally applies to agency
recognized parts rated for better than
functional isolation where the wire enamel
insulation is always supplemented by a
further insulation system of physical spacing
or barriers.
