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78 Cards in this Set
- Front
- Back
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What is a class A bond?
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Metallic surfaces bonded by welding or brazing.
MIL-STD-1310G(NAVY) |
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What is a class B bond?
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Metallic surfaces bonded by bolting or clamping.
MIL-STD-1310G(NAVY) |
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What is a class C bond?
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Metallic surfaces bonded by bridging them with a metallic (conductive) bond strap.
MIL-STD-1310G(NAVY) |
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What is a class C type I bond?
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Corrosive resistant Steel (CRES)316 1/4-inch wire rope with lugs of CRES316L SCHED 80S pipe. (needs mounting bosses)
MIL-STD-1310G(NAVY) |
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The Triangulation method is most effective for measuring ______ systems and is not recommended for ______.
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single rod ground, multi-rod configurations.
MIL-STD-1310G(NAVY) |
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What is a class C type II bond?
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Flat CRES316 w/ mounting holes at each end
MIL-STD-1310G(NAVY) |
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What is a class C type III bond?
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Flat Copper with mounting holes in each end.
MIL-STD-1310G(NAVY) |
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What is a class C type IV bond?
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Flat copper braid with mounting holes in each end.
MIL-STD-1310G(NAVY) |
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Computer systems can require what? Why?
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Separate hardwired ground system installed
Isolate power supplies MIL-STD-1310G(NAVY) |
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Equiment cases, cabinets housings, and any exposed conductive metal must have a contact resistance of ______ohm to ground.
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.1ohm
MIL-STD-1310G(NAVY) |
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The AC resistance across grounding and bonding junctions should not exceed ___________.
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25ohm @ 30MHz
MIL-STD-1310G(NAVY) |
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What types of bonding straps can be used topside on a ship?
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Type I and II
CRES wire/strap MIL-STD-1310G(NAVY) |
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What types of bonding straps can be used below decks of a ship?
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Type III and IV
Copper Strap/braid MIL-STD-1310G(NAVY) |
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What class bonding should be used when movability is not a factor?
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Class A
MIL-STD-1310G(NAVY) |
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What class bonding should be used when movability is a factor?
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Class B or C
MIL-STD-1310G(NAVY) |
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What two factors must a piece of equipment have to have to require grounding?
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External power source and 30V or more
MIL-STD-1310G(NAVY) |
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T/F
Something bonded with a class A bond is considered a part of the ships ground plane and can be used to ground other things. Class B? Class C? |
Class A=T
Class B=F Class C=F MIL-STD-1310G(NAVY) |
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What manual governs the specific type of hardware used in Class B & C bonding?
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MIL-DTL-24749
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T/F
It is acceptable to drill holes in an enclosure for bond stap installation. |
F
MIL-STD-1310G(NAVY) |
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When should a Type I bond strap be used?
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Topside
Metal to Metal Hull-generated EMI sources MIL-STD-1310G(NAVY) |
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When should a Type II bond strap be used?
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Topside
Metal to metal EMI sourses eg. antenna, tuners, couplers, enclosures, and cabinets MIL-STD-1310G(NAVY) |
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When should a Type III bond strap be used?
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Below Decks
Equipment, Enclosures, and Cabinets MIL-STD-1310G(NAVY) |
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When should a Type IV bond strap be used?
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Below Decks
Sound isolated mounts or shock mounts (non-metallic mounts). MIL-STD-1310G(NAVY) |
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When is bonding not recommended?
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Emergency Equipment
Moving Hardware Quick release fittings MIL-STD-1310G(NAVY) |
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Unshielded cables that exceed ___ ft. require EM shielding or filter.
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3ft
MIL-STD-1310G(NAVY) |
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Non conducting equipment may be exempted from requiring a grounded conductor if_______________.
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Marked as Double Insulated
or meets both Passes rugged/ safe inspection and has >1Mohm resistance from any phase conductor to any exposed metal part MIL-STD-1310G(NAVY) |
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What size cable should be used as an Electronic Transmitter Ground Cable.
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0000AWG from main ground to radio transmitter spaces.
MIL-STD-1310G(NAVY) |
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What size cable should be used to connect each transmitter to the Electronic Transmitter Ground Cable from the main ground?
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1AWG
MIL-STD-1310G(NAVY) |
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What should be provided when couplers and tuners are mounted to nonmetalic masts or structures?
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10AWG Ground system
MIL-STD-1310G(NAVY) |
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What size cable should be used to connect a mast to the ground plane?
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0000AWG
MIL-STD-1310G(NAVY) |
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What amperage is a typical peak for a lightning flash?
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20kA or Higher
MIL-HDBK-419A |
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Water pipes typically display a resistance of ________ to ground.
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<3ohms
MIL-HDBK-419A |
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What resistance to ground for a grounding electrode is consider the highest acceptable amount but should only be used in homes and other low power facilities?
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25ohms
MIL-HDBK-419A |
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A design goal of ____ohms on a ground electrode system should be attained at reasonable cost.
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10ohm
MIL-STD-188-124B 5.1.1.1.3.1 |
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What are the four grounding sub-system types?
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Lightning Protection
Fault Protection Signal Reference Earth Electrode MIL-HDBK-419A |
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Which grounding sub-system type provides the benifit of lightning protection, fault protection, and signal reference to earth?
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Earth Electrode
MIL-HDBK-419A |
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What is the general design of an earth electrode ground system?
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Ring of ground conductors around periphery of building or tower
MIL-HDBK-419A |
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What is the most preferable earth electrode subsystem design.
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10ft/3m minimum ground rods every 15ft/4.5m
MIL-HDBK-419A |
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What is the worst case earth electrode subsystem design?
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Grid under building extending 2-6ft/.6-1.8m past drip line with radial or horizontal conductors extending 125/37.5m
MIL-HDBK-419A |
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What size is the most common acceptable ground rod?
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1.9cm/3/4" diameter
3m/10' length Copper-clad Steel Note:Copper-clad steel neccessary to withstand driving force. MIL-HDBK-419A |
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How deep should horizontal ground conductors be buried?
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.48-.86m/18"-36"
MIL-HDBK-419A |
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How deep should ground grids be buried?
What should the spacing between conductors of a grid be? |
15.24cm/6" deep
.6-1.2m/2-4' spacing MIL-HDBK-419A |
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Grounding plates should be how big?
Thick? Iron/steel? Non-Ferrous? Deep? |
size=.09m square/2 square feet
Iron/Steel=.64cm/1/4' thick Non-Ferrous=.15cm/.06inches deep=1.5-2.4m/5-8ft MIL-HDBK-419A |
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T/F
Metal framework of a building/water pipes/incidental metals/ well casings can be used a part of a earth electrode subsystem? |
T
Must <10ohm MIL-HDBK-419A |
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What are two techniques to reduce soil resistivity?
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Water Retention
Chemical Salting MIL-HDBK-419A |
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What are the acceptable salting chemicals to reduce soil resistivity?
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Magnesium Sulphate MgSO4=epsom salt
Copper Sulphate CuSO4= blue vitriol Calcium Chloride CaCl2 Sodium Chloride NaCl=common salt Potassium Nitrate KNO3=saltpeter MIL-HDBK-419A |
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What clouds are associated with Thunder storms? How tall can the get?
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Cumulonimbus
15-20km/9-12miles |
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What determines AC Impedance?
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AC resistance and Reactance
MIL-HDBK-419A |
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What concept causes AC Impedance to vary with frequency?
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Skin Effect
MIL-HDBK-419A |
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When multiple conductor are run closely together what causes an increased AC resistance?
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Proximity Effect
MIL-HDBK-419A |
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What are the advantage and disadvantages of a Floating Ground system?
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Isolated from building ground best for noise isolation.
Builds up static charge. MIL-HDBK-419A |
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What are the advantage and disadvantages of a Single Point ground system?
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Very high cost
Many conductors Not good with high frequencies MIL-HDBK-419A |
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When would you use a multi-point ground system?
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High frequency systems
30-300 kHz MIL-HDBK-419A |
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What is the definition of bonding?
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Process by which a low impedance path for the flow of an electric current is established between two metallic objects.
MIL-HDBK-419A |
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A high quality bond is considered to have a DC resistance of ________?
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1 milliohm
MIL-HDBK-419A pg.7-3 |
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What is the maximum dc resistance for noise minimization?
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50 miliohms
MIL-HDBK-419A |
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What techniques offer the lowest values of bond resistance?
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Welding
Brazing Silver Soldering MIL-HDBK-419A |
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What temperature does welding occur?
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in excess of 4000degrees F
MIL-HDBK-419A |
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Which bonding is best and should always be used when possible for permanent joints?
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Welding
MIL-HDBK-419A |
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A technique that involves, a mixture of aluminum, copper oxide, and other powders held in place by a graphite mold is called what?
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Exothermic Process
MIL-HDBK-419A |
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What is Brazing? Temp?
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800deg.F
filler metal with appropriate flux. MIL-HDBK-419A |
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Are soft solders allowed for bonding? Why?
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No, low mechanical strength and possible crystalization
MIL-HDBK-419A |
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What resistance should a strap used in an indirect bond have?
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.1 milliohm
MIL-HDBK-419A |
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In order to keep contaminents out of a bond how quickly should a bond be attached after prep?
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30min
if 2hrs.+ are required a temp. protective covering is required MIL-HDBK-419A |
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How many death occur a year due to electric shock?
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1000
MIL-HDBK-419A |
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What happens at 0-1mA AC and 0-4 mA DC?
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Perception Current
MIL-HDBK-419A Table 9-1 |
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What happens at 1-4mA AC and 4-15 mA DC?
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Reaction Current
MIL-HDBK-419A Table 9-1 |
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What happens at 4-21mA AC and 15-80mA DC?
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Reflex Action(Let-Go Current)
MIL-HDBK-419A Table 9-1 |
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What happens at 21-40mA AC and 80-160mA DC?
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Muscular Inhibition
MIL-HDBK-419A Table 9-1 |
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What happens at 40-100mA AC and 160-300mA DC?
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Respitory Block
MIL-HDBK-419A Table 9-1 |
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What happens at Over 100mA AC and Over 300mA DC?
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Usually Death
MIL-HDBK-419A Table 9-1 |
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What resistance is human skin usually considered to be?
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500-1500ohms
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What are the classes of lasers?
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Class1 Non-Hazardous
Class2 Depend on blink reflex Class3 Direct or specular reflection hazard Class4 All other High energy |
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Ground rods shall be connected with ____ and buried at least _____.
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1/0 AWG copper
.45m/1.5f MIL-STD-188-124B |
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What is the only acceptable method to check resistance to earth of a electrode subsystem?
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Fall potential technique
MIL-STD-188-124B |
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Waveguides shall be grounded with ____?
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solid copper strap or wire at least equal to 6AWG
MIL-STD-188-124B |
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Shielding is more effective/easier at Higher/Lower frequencies?
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Higher
MIL-STD-188-124B |
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Single Point grounds offer the most effective grounds at ______ but ________ multi-point is more beneficial.
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lower frequencies
above 300kHz sometimes 30kHz |
