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Frequently asked questions

Your Questions answered…

If there are questions which have not been answered in this section please e mail us and we shall do our best to answer them.

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Q1 What is EMPulse?

EMPulse is a handheld instrument especially designed to locate EMI issues, give a primary check of circuitry at PCB level  and pre-compliance EMC immunity checking

Q2 How does EMPulse work?

By generating electrical and magnetic pulses near your PCB design, EMPulse recreates symptoms which could cause equipment  to fail during the mandatory CE immunity test. EMPulse can  then be used to locate the problem area.

Q3 When do I need EMPulse?

If your equipment has failed the mandatory EMC compliance  tests due to ESD or RF immunity and you need to locate  a problem. To prevent future design failures, use EMPulse  during the initial design stage.

Q4 Can I use EMPulse to replace the CE electromagnetic immunity tests?
A4 No. Equipment will still require mandatory testing, but checking your design with EMPulse will give you a much better chance  of passing first time
Q5 How long does it take to set up EMPulse?

A few seconds! Read the manual and see the free video for details.

Q6 it possible to check electronic circuitry before it  is placed in a screened enclosure?

Yes, EMPulse gives rapid and repeatable EMI checks on PCB  level electronic circuitry

Q7 Can EMPulse exactly locate a problem?

Yes, when synchronised to an oscilloscope, it can precisely locate a signal causing a problem.

Q8 How repeatable are EMPulse results?

Very- Because there are no connections required to the circuitry under test , EMPulse provides very consistent results

Q9 Will EMPulse affect a well-designed PCB?

No. A well laid out PCB with ground plane and no exposed  high impedance signals should not be affected by the EMPulse  sweep at 10 mm on full power

Q10 What sort of field does EMPulse generate?

EMPulse generates Electrical and Magnetic field of short  Uni-polar pulses with low average energy.

Q11 The EMC regulations are regularly being updated,
will EMPulse become obsolete like some other EMC test gear?

EMPulse will not become obsolete as the EMI standards are updated. Electronic circuitry will always require fault location  and a primary level of immunity

Q12 Can I check internal equipment wiring for electromagnetic immunity using EMPulse?

Yes, use the long side of the large EMPulse probe parallel  to a cable to induce pulses into the cable.

Q13 How accurately can I locate a fault without using a oscilloscope?

Usually the problem can be pinpointed simply by sweeping EMPulse while reducing the field strength,The key to locating a fault is to sweep closer or touching the area whilst  reducing the power. By setting the power so that it only  just affects the problem the area can usually be accurately found.

Q14 Can EMPulse save me money on my new designs?

EMPulse can be used on existing designs to identify sensitive areas at a primary level, if these areas are improved then  it may be possible to make savings in the enclosure design. Once changes have been made EMPulse can be used to verify  the problem is solved.

Q15 At what stage should I use EMPulse to check my circuit  design?

As soon as the circuit is laid out on a PCB and working normally. EMPulse has been developed to assist in locating EMC immunity problem areas in electronic circuits at the earliest opportunity.

Q16 Why does EMPulse have separate Positive and Negative pulse buttons?

Circuits can be affected differently by each polarity, this  can sometimes give a clue to the source of the problem. EMPulse  uses polarised pulses, which can show up problems that symmetric pulses may not show.

Q17 What are the typical symptoms that can occur in the EUT due to the EMPulse field?

Displays may be corrupted / Power Supplies may glitch or  fluctuate / Processors may glitch or reset / Noise may be  induced into audio circuits / Memory may be corrupted / Circuits  may latch up / Logic may change state erratically. All these  symptoms indicate a problem in the circuit design or layout

Q18 How do I sweep a PCB using EMPulse?

EMPulse is held perpendicular to the circuitry and swept  parallel to the PCB tracks. On multi layer PCB’s  with ground or power planes then both sides of the board  need to be checked.

Q19 How do I check a circuit for possible problem areas?

With power applied and the circuit working normally, the EMPulse probe is used to scan within a few cm’s of  the electronic circuitry, whilst looking for any signs  of malfunction.

Q20 How does the EMPulse oscilloscope sync feature work?

By connecting the EMPulse sync output to the scope trig input, this allows EMPulse electromagnetic field pulse to be aligned  on with the ‘scope display and thus allows signals  to be interrogated for any EM field affecting them.

Q21 Can I press both Positive and Negative pulse buttons at the same time?

Yes. EMPulse will then generate alternating Uni-polar pulses, which will expose most problems. This is the best way to begin your scan for problem areas.

Q22 Does EMPulse affect signals in ribbon cabling?

Balanced signals and those with a local, well defined return  path will not be affected, i.e. balanced ground returns  in the cable. Unbalanced signals where the signal return  path does not follow the signal may be affected

Q23 What sort of design circuit flaws can EMPulse expose?

Poor current return paths in ground planes, for example when  a ground plane is not continuous under the signal path. / Unbalanced signal traces / Un-terminated high impedance signals etc

Q24 What if I have an intentionally high impedance signal?

You must be aware that EMPulse will probably affect the signal. You will have to ensure your design sufficiently screens  this signal from external voltage fields to meet CE regulations

Q25 Will EMPulse give me false alarms?

Possibly, but It is much better to be aware of EMI issues  early in the design stage. By making the initial circuitry  robust to EMI issues, both safety and reliability can be improved

Q26 Should I only scan the area where the ES discharge occurred
when looking for the cause of the problem?

No. ESD related problems can also be caused by the magnetic fields generated when the high ESD currents flow through conductive parts of an enclosure. These may not be local  to the ESD spark.

Q27 Can I do quick checks on circuitry to assess improvements  in the design?

Yes. Because there are no connections required between EMPulse and the circuitry under test, EMPulse is very quick to use  and it provides consistent results

Q28 Why is the EMPulse probe such an  odd shape?

To make fault location easy! The long edges can induce a field over a wide area of circuitry allowing a rapid sweep, the short edge at the tip allows a smaller area to be located, and the tip focuses the field even more.

Q29 Can I check equipment that is still in its enclosure?

Yes, Precise fault finding can be done by getting down to  PCB level in both small and large equipment.

Q30 Can I check large equipment enclosures for susceptibility  to ESD and RF fields?

Yes, EMPulse allows individual circuitry and wiring inside  the cabinet to be assessed for immunity, thus giving an idea  of the overall immunity.

Q32 Can I use EMPulse to check transformer shielding?

Yes. Transformers use magnetic field as their transfer medium  and so are always sensitive to external magnetic fields  and in some cases this can cause problems. Audio transformers  are often magnetically screened. This prevents 'hums' and  'buzzes' being picked up. By scanning EMPulse around the  transformer with the 'FREQUENCY' control set to 1 KHz a  tone may be heard from a poorly shielded audio transformer. Light dimmers and isolated control mechanisms also use transformers  (although not always screened) in this case EMPulse may cause  a light dimmer to flicker, or a control to malfunction indicating  a problem could be lurking.

Q33 Can I test the effectiveness of magnetic screening?

Yes. By using your oscilloscope with EMPulse and the EMCheck probe set to magnetic, a measurement is then taken. The  shielding is placed between the two probes for a further  measurement and the then the relative strengths can be  compared

Q34 I have a problem with my new design, ESD is causing spurious effects
on my processor, can I use EMPulse to locate the  cause of this?

Yes, because EMPulse is used in the very near field, it can  usually locate any issues that are revealed in the in the  final EMI testing phase

Q35 Is the EMPulse field strength powerful enough to fully  test my circuits?

EMPulse field, power output and frequency spectrum are sufficient to locate most EMI issues that occur at PCB level in commercial and industrial designs.

Q36 My equipment has failed the final mandatory CE ESD test, 
how do I locate the problem?

Scan the Equipment under Test using EMPulse to precisely  locate electronic circuitry sensitive to electric and magnetic  fields generated by high currents in conductive surfaces  when ESD discharges occur.

Q37 Are there ESD immunity problems that EMPulse cannot locate?

Problems in the equipment under test caused by internal arcing from the enclosure to internal circuits will often be so  severe that the field from EMPulse will not be able to  locate this type of problem,

Q38 Are there any RF immunity problems in my design that EMPulse cannot locate?

If the final RF immunity test shows problems only when the  EUT is exposed to fields above 500 MHz then the field generated  by EMPulse may not expose the problem. However, a lot of  very high frequency problems also have symptoms at lower  frequencies.

Q39 Is there an On/Off switch on EMPulse?

No. EMPulse auto power On/Off feature ensures the instrument  is always instantly ready for use

Q40 What happens when the EMPulse rechargeable batteries are exhausted?

EMPulse will sustain the same field strength until the batteries  start to fail, at which point a green LED will flash several  time then EMPulse will switch off.

Q41 Can I charge EMPulse whilst using the instrument?

Yes, but it is not recommended, EMPulse electrical field  return path will be affected by the changer connection,  giving inconsistent results. Note that after 1 minute of  inactivity EMPulse will enter charge mode until the batteries  are fully charged.

Q42 How long do the batteries last?

EMPulse operates continuously for many hours on one charge  of it internal batteries, this equates to several days  of testing.

Q43 Can I ‘top up’ the battery  charge in EMPulse?

Yes, the internal intelligent battery charger will not overcharge  the batteries.

Q44 Is EMPulse cost effective?

Yes, if EMPulse can save you just one failure at the final  EMC tests then it has justified its cost. It will also  give improved confidence in future designs as to the Electro  Magnetic Immunity of your products. EMPulse is an affordable  option for pre compliance testing, allowing every electronic  engineer to have one at hand to expose potential issues.

Q45 Why do Electronic Engineers need EMPulse?

EMPulse enables an electronic design engineer to regularly  check his new designs to reduce the chance of a future  problems occurring, where they can be costly to rectify.  Most electronic engineers have encountered EMI problems  and will be pleased to be able to identify them early in  the design.

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