©2002 Teccor Electronics E0 - 3 http://www.teccor.com 
Thyristor Product Catalog +1 972-580-7777
Electrical Parameter Terminology
Thyristor
di/dt (Critical Rate-of-rise of On-state Current) – Maximum 
value of the rate-of-rise of on-state current which a thyristor can 
withstand without deleterious effect
dv/dt (Critical Rate-of-rise of Off-state Voltage or Static 
dv/dt) – 
Minimum value of the rate-of-rise of principal voltage 
which will cause switching from the off state to the on state
dv/dt(c) Critical Rate-of-rise of Commutation Voltage of a 
Triac (Commutating dv/dt) – 
Minimum value of the rate-of-rise 
of principal voltage which will cause switching from the off state 
to the on state immediately following on-state current conduction 
in the opposite quadrant
I2t (RMS Surge (Non-repetitive) On-state Fusing Current) – 
Measure of let-through energy in terms of current and time for 
fusing purposes
I
BO 
(Breakover Current) – Principal current at the breakover 
point
I
DRM 
(Repetitive Peak Off-state Current) – Maximum leakage 
current that may occur under the conditions of V
DRM
IGT (Gate Trigger Current) – Minimum gate current required to 
switch a thyristor from the off state to the on state
IH (Holding Current) – Minimum principal current required to 
maintain the thyristor in the on state
IPP (Peak Pulse Current) – Peak pulse current at a short time 
duration and specified waveshape
I
RRM 
(Repetitive Peak Reverse Current) – Maximum leakage 
current that may occur under the conditions of V
RRM
IS (Switching Current) – Current at V
S
 when a sidac switches 
from the clamping state to on state
I
T(RMS) 
(On-state Current) – Anode cathode principal current 
that may be allowed under stated conditions, usually the fullcycle RMS current
I
TSM
 (Surge (Non-repetitive) On-state Current) – Peak single 
cycle AC current pulse allowed
P
G(AV)
 (Average Gate Power Dissipation) – Value of gate 
power which may be dissipated between the gate and main terminal 1 (or cathode) average over a full cycle
PGM (Peak Gate Power Dissipation) – Maximum power which 
may be dissipated between the gate and main terminal 1 (or 
cathode) for a specified time duration
R
θJA
 (Thermal Resistance, Junction-to-ambient) – Tempera-
ture difference between the thyristor junction and ambient divided 
by the power dissipation causing the temperature difference 
under conditions of thermal equilibrium
Note: Ambient is defined as the point where temperature does 
not change as a result of the dissipation.
R
θJC
 (Thermal Resistance, Junction-to-case) – Temperature 
difference between the thyristor junction and the thyristor case 
divided by the power dissipation causing the temperature difference under conditions of thermal equilibrium
tgt (Gate-controlled Turn-on Time) – Time interval between 
the 10% rise of the gate pulse and the 90% rise of the principal 
current pulse during switching of a thyristor from the off state to 
the on state
tq (Circuit-commutated Turn-off Time) – Time interval 
between the instant when the principal current has decreased to 
zero after external switching of the principal voltage circuit and 
the instant when the SCR is capable of supporting a specified 
principal voltage without turning on
VBO (Breakover Voltage) – Principal voltage at the breakover 
point
V
DRM
 (Repetitive Peak Off-state Voltage) – Maximum allow-
able instantaneous value of repetitive off-state voltage that may 
be applied across a bidirectional thyristor (forward or reverse 
direction) or SCR (forward direction only)
V
GT 
(Gate Trigger Voltage) – Minimum gate voltage required to 
produce the gate trigger current
V
RRM
 (Repetitive Peak Reverse Voltage) – Maximum allow-
able instantaneous value of a repetitive reverse voltage that may 
be applied across an SCR without causing reverse current avalanche
VS (Switching Voltage) – Voltage point after V
BO
 when a sidac 
switches from a clamping state to on state
VT (On-state Voltage) – Principal voltage when the thyristor is in 
the on state
Diode Rectifiers
I
F(AV)
 (Average Forward Current) – Average forward conduc-
tion current
IFM (Maximum (Peak) Reverse Current) – Maximum reverse 
leakage current that may occur at rated V
RRM
I
F(RMS)
 (RMS Forward Current) – RMS forward conduction cur-
rent
I
FSM
 (Maximum (Peak) Forward (Non-repetitive) Surge 
Current) – 
Maximum (peak) forward single cycle AC surge cur-
rent allowed for specified duration
VFM (Maximum (Peak) Forward Voltage Drop) – Maximum 
(peak) forward voltage drop from the anode to cathode at stated 
conditions
VR (Reverse Blocking Voltage) – Maximum allowable DC 
reverse blocking voltage that may be applied to the rectifier
V
RRM
 (Maximum (Peak) Repetitive Reverse Voltage) – Maxi-
mum peak allowable value of a repetitive reverse voltage that 
may be applied to the rectifier