Technical informations, Combination d-sub connectors δ, F π σ µ – Northern Connectors Conec D-Sub Combination Connectors User Manual
Page 6
Ambient temperature (°C)
Working current in amperes (A)
Limit temperature
6|5
High voltage contacts
Combination D-SUB Connectors
δ =
√
f π σ µ
0
µ
r
1
Skin effect
Technical informations
Alternating currents do not uniformly occupy the entire cross section of the conductor, rather inductance effect in the conductor deflects the
current towards the surface of the conductor, whereby this deflection increases with the frequency.
The resistive attenuation of a transmission line increases with the frequency as a result of this skin effect.
The skin depth (equivalent thickness of the layer in which current flows) can be determined using
f = frequency
σ = conductivity of the conductor material
σ
Ag
= 62 x 10
6
S m
σ
Cu
= 58 x 10
6
S m
µ
0
= 1,256 10
6
Vs Am
µ
r
... relative permeability constant for the employed material
VSWR-Value
The ratio between the value of the largest and the smallest voltages on a loss-free line is known as the ripple or voltage standing wave ratio
s (where 1 m 1 ∞). The reciprocal value of the VSWR is known as the inverse voltage standing wave ratio m (where 0 m 1).
(VSWR = Voltage standing ware ratio)
The value of is linked with the reflection coefficient r on s transmission line according to the equation
Current Rating
(1 + IrI)
(1
_
IrI)
s =