On Oct 2, 12:44 pm, Douglas Johnson wrote:
I've seen you make this claim many times. Could you please give a reference to
a manufacturer's data sheet on a common appliance (TV, computer, stereo) with
surge protection data?
If seeking "surge protection data", then you are asking the wrong
question. Industry standards define how much surge an appliances
should withstand without damage. A 1970 industry standard defined 600
volts without damage for 120 volt electronic appliances. Those old
standards existed long before PCs even existed.
Other standards: For example, Ethernet ports must withstand 2000
volts.
Even low voltage interface ICs now contain 2000 or 15,000 volt
internal protection as even required by an IEC standard. A USB
interface chip datasheet demonstrates that standard:
http://datasheets.maxim-ic.com/en/ds/MAX3349EA.pdf
Telco standards require phone appliances to withstand a metallic
voltage of 800 V max and a longitudinal voltage of 1500 V max. I
believe may be from FCC Part 68. The point: so many standards define
internal protection that I am only grabbing random examples.
One ATX power supply spec (sorry - forgotten which one) said:
Section 3.1.4.2 Surge Voltages
The peak value of the injected unipoloar wave form shall be
2.0 kV measured at the input of the power supply for the
common and normal modes of transient surge injection.
The surge withstand test must not produce:
Damage to the power supply
Disruption of the normal operation of the power supply
Output voltage deviation exceeding the limits of Section 3.2.1.
All appliances contain some protection. Those who never learned this
stuff will then deny when a varistor or avalanche diode cannot be
found. Protection is integrated into every design including dimmer
switches. If a manufacturer is being honest, those numbers appear in
manufacturer specifications (a reference to power supplies marketed to
the electrically challenged such as A+ Certified computer techs).
Since surge protection myths are so widespread, most do not even know
that every appliance contains internal protection. If this was known,
then many would start asking embarrassing questions that plug-in
protector manufacturers do not want to answer.
How to sell power supplies to the electrically challenged? Provide
no manufacturer specs. Sell a power supply that is missing essential
functions (ie to A+ Certified Computer techs) at lower price and
higher profits. When an inferior supply fails, then blame a surge;
not the missing internal protection and not the electrically naive
computer assembler.
So widespread is technical ignorance that most people also do not
know phone lines have protection installed free by the telco at every
subscriber interface.
Requested were sources for protection inside every appliance.
Provided are examples of industry standards that only the few
electrically knowledgeable would know. With so many electrically
naive consumers (who don't even know that all appliances contain some
protection), then the market is also ripe for selling a $3 power strip
with some ten cent parts for $150.
All appliances contain internal protection. Why can this 120 volt
computer grade UPS output 200 volt square waves with a spike of up to
270 volts between those square waves? This UPS output may even harm
some small electric motors and power strip protectors. But protection
in all computers makes this dirty 'modified sine wave' irrelevant
(cause no damage). Why does that dirty UPS output not harm
computers? Because all computers are required (by industry standards)
to contain protection that makes 'dirty' UPS electricity irrelevant.
Just another example of protection routinely installed in all
appliances.
Enough examples? Furthermore, the examples also came with
numbers. Those who only speculate also don't provide numbers. Why
numerous examples when a clear majority did not know of protection
routinely in electronics? Well, the majority also knew Saddam had
WMDs. A typical example explains why technical knowledge is so ra A
+ Certified computer techs need not know anything about electricity to
be certified.