With the development of electrical and electronic technology, the
world entered the information age, the increasing popularity of
home appliances and electronic products, radio and television, post
and telecommunications, and computers and their networks become
increasingly developed, increasingly complex electromagnetic
environment and deterioration, tend to make electronic and
electrical equipment or the system does not work, causing decreased
performance and even damage, the electromagnetic compatibility of
electrical and electronic products more and more governments and
manufacturer attention.
For example, when we watch TV, if next to someone using the hair
dryer or electric razor like household appliances, will appear on
the screen objectionable snow stripes. Undercooked rice cooker to
cook rice, it's clear the air conditioners turned off, but after a
while start their own ... ... these are common to electromagnetic
interference. More seriously, if the signal prevents
electromagnetic interference of medical illness is monitoring
electronic equipment, or when the aircraft is flying, will result
in disastrous consequences. Therefore, EMC and more important in
the product.
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Prime Time has experienced more than EMC design experts, can
provide EMC design of production systems (including structure,
devices), on board to provide PCB design layout EMC solutions and
provide guidance and EMC solutions of system (including structural
, cable) and other services.
In the electrical and mechanical design principles, Prime Time has
a good application base, to ensure that EMC design with excellent
quality, by schematic analysis, device selection, board structure,
high-speed signal simulation SI, PCB.layout wiring and other
measures at the design stage for the board to solve your EMC
product issues, specifically in the following areas:
1, a potential source of interference and the electromagnetic
energy sensitive components and circuit device mounted on a PCB,
the active components of the position, the alignment of printed
lines, impedance matching, grounding design, etc., we are in the
EMC design be taken into account, some PCB components will be
masked.
2, the internal cable is generally used to connect the PCB or other
internal sub-components, including alignment methods and EMC
shielding the internal cable design.
3, the EMC in the PCB design and the internal cable design is
completed, we will pay particular attention to shielding design of
chassis and all the cracks, through-hole punch and cable handling
4, in particular, to focus on input, output power and other cables
filtering
EMC EMC design the basic principles:
Electronic circuit design criteria consider only the electronic
circuit designer is often the product's features and functionality,
and electromagnetic compatibility have not considered, so the
product is the completion of its function, but also generated a lot
of features of sexual harassment and other harassment. Also, can
not meet the sensitivity requirements. EMC design of electronic
circuits from the following considerations:
In most cases, component selection, circuit electromagnetic
characteristics of the basic components to meet will determine the
degree of functional units and equipment to meet the
electromagnetic compatibility of the final level. Select the
appropriate criteria, including the electromagnetic component of
the main band features and circuit assembly technology. To achieve
electromagnetic compatibility because it is often far from the
fundamental frequency component from the response to the decision.
In many cases, the circuit assembly also decided that the band
response (such as lead length) and the coupling among the different
circuit elements level. Specific rules are:
, at high frequencies, and lead type capacitors, compared with
priority into a small lead inductance capacitor feedthrough filter
capacitor or bearing.
, in the capacitor leads must be used, consider the lead inductance
of the filter efficiency.
, aluminum electrolytic capacitors may occur a few microseconds of
transient dielectric breakdown, which in a large ripple or
transient voltage circuit, you should use solid capacitors.
, parasitic inductance and capacitance using a small resistor. Chip
resistor can be used for ultra-high frequency bands.
, large inductance large parasitic capacitance, in order to improve
the low frequency part of the insertion loss, do not use a single
filter, but rather the use of certain multi-section composed of a
small inductor fil |
