Fuse Selection Criteria
2002 Teccor Electronics
SIDACtor
Data Book and Design Guide
5 - 9
http://www.teccor.com
+1 972-580-7777
T
Peak Pulse Current (I
PP
)
For circuits that do not require additional series resistance, the surge current rating (I
PP
) of
the fuse should be greater than or equal to the surge currents associated with the lightning
immunity tests of the applicable regulatory requirement (I
PK
):
I
PP
I
PK
For circuits that use additional series resistance, the surge current rating (I
PP
) of the fuse
should be greater than or equal to the
available surge currents associated with the lightning
immunity tests of the applicable regulatory requirement (I
PK(available)
):
I
PP
I
PK(available)
The maximum available surge current is calculated by dividing the peak surge voltage (V
PK
)
by the total circuit resistance (R
TOTAL
):
I
PK(available)
= V
PK
/R
TOTAL
For longitudinal surges (Tip-Ground, Ring-Ground), R
TOTAL
is calculated for both Tip and
Ring:
R
SOURCE
= V
PK
/I
PK
R
TOTAL
= R
TIP
+ R
SOURCE
R
TOTAL
= R
RING
+ R
SOURCE
For metallic surges (Tip-Ring):
R
SOURCE
= V
PK
/I
PK
R
TOTAL
= R
TIP
+ R
RING
+ R
SOURCE