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2002 Teccor Electronics
Thyristor Product Catalog(972) 580-7777
Product Descriptions
Thyristors
A thyristor is any semiconductor switch with a bi-stable action 
depending on p-n-p-n regenerative feedback. Thyristors are nor-
mally two- or three-terminal devices for either unidirectional or bi-
directional circuit configurations. Thyristors can have many forms, 
but they have certain commonalities. All thyristors are solid state 
switches that are normally open circuits (very high impedance), 
capable of withstanding rated blocking/off-state voltage until trig-
gered to on state. When triggered to on state, thyristors become a 
low-impedance current path until principle current either stops or 
drops below a minimum holding level. After a thyristor is triggered 
to on-state condition, the trigger current can be removed without 
turning off the device. Thyristors are used to control the flow of 
electrical currents in applications including:
Home appliances (lighting, heating, temperature control, alarm 
activation, fan speed)
Electrical tools (for controlled actions such as motor speed, sta-
pling event, battery charging)
Outdoor equipment (water sprinklers, gas engine ignition, elec-
tronic displays, area lighting, sports equipment, physical fitness)
Sensitive Triacs
Teccor's sensitive gate triacs are AC bidirectional silicon
switches that provide guaranteed gate trigger current levels in 
Quadrants I, II, III, and IV. Interfacing to microprocessors or other 
equipment with single polarity gate triggering is made possible with 
sensitive gate triacs. Gate triggering currents of 3 mA, 5 mA, 
10 mA, or 20 mA may be specified.
Sensitive gate triacs are capable of controlling AC load currents 
from 0.8 A to 8 A rms and can withstand operating voltages from 
200 V to 600 V.
Triacs
Teccor's triac products are bidirectional AC switches, capable of 
controlling loads from 0.8 A to 35 A rms with 10 mA, 25 mA, and 
50 mA I
GT
 in operating Quadrants I, II and III.
Triacs are useful in full-wave AC applications to control AC power 
either through full-cycle switching or phase control of current to the 
load element. These triacs are rated to block voltage in the “OFF” 
condition from 200 V minimum with selected products capable of 
1000 V operation. Typical applications include motor speed con-
trols, heater controls, and incandescent light controls.
Quadrac
Quadrac
 devices, originally developed by Teccor, are triacs and 
alternistor triacs with a diac trigger mounted inside the same pack-
age. These devices save the user the expense and assembly time 
of buying a discrete diac and assembling in conjunction with a 
gated triac.
The 
Quadrac
is offered in capacities from 4 A to 15 A rms and volt-
ages from 200 V ac to 600 V ac.
Alternistor Triacs
The Teccor alternistor is specifically designed for applications 
required to switch highly inductive loads. The design of this special 
chip effectively offers the same performance as
two thyristors 
(SCRs) wired inverse parallel (back-to-back).
This new chip construction provides the equivalent of two electri-
cally-separate SCR structures, providing enhanced dv/dt charac-
teristics while retaining the advantages of a single-chip device.
Teccor manufactures 6 A to 40 A alternistors with blocking voltage 
rating from 200 V to 1000 V. Alternistors are offered in TO-220, 
TO-218, and TO-218X packages with isolated and non-isolated 
versions.
Sensitive SCRs
Teccor's sensitive gate SCRs are silicon-controlled rectifiers repre-
senting the best in design, performance, and packaging techniques 
for low- and medium-current applications.
Anode currents of 0.8 A to 10 A rms can be controlled by sensitive 
gate SCRs with gate drive currents ranging from 12 μA to 500 μA. 
Sensitive gate SCRs are ideally suited for interfacing to integrated 
circuits or in applications where high current load requirements and 
limited gate drive current capabilities exist. Examples include igni-
tion circuits, motor controls, and DC latching for alarms in smoke 
detectors. Sensitive gate SCRs are available in voltage ratings to 
600 V ac.
SCRs
Teccor's SCR products are half-wave, silicon-controlled rectifiers 
that represent the state of the art in design and performance.
Load current capabilities range from 1 A to 70 A rms, and voltages 
from 200 V to 1000 V may be specified to meet a variety of appli-
cation needs.
Because of its unidirectional switching capability, the SCR is used 
in circuits where high surge currents or latching action is required. 
It may also be used for half-wave-type circuits where gate-con-
trolled rectification action is required. Applications include crow-
bars in power supplies, camera flash units, smoke alarms, motor 
controls, battery chargers, and engine ignition.
Surge current ratings are available from 30 A in the TO-92 packag-
ing to 950 A in the TO-218X package.
Rectifiers
Teccor manufactures 15 A to 25 A rms rectifiers with voltages 
rated from 200 V to 1000 V. Due to the electrically isolated TO-220 
package, these rectifiers may be used in common anode or com-
mon cathode circuits using only one part type, thereby simplifying 
stock requirements.
Diacs
Diacs are trigger devices used in phase control circuits to provide 
gate pulses to a triac or SCR. They are voltage-triggered bidirec-
tional silicon devices housed in DO-35 glass axial lead packages 
and DO-214 surface mount packages.
Diac voltage selections from 27 V to 45 V provide trigger pulses 
closely matched in symmetry at the positive and negative break-
over points to minimize DC component in the load circuit.
Some applications include gate triggers for light controls, dimmers, 
power pulse circuits, voltage references in AC power circuits, and 
triac triggers in motor speed controls.
Sidacs
Sidacs represent a unique set of thyristor qualities. The sidac is a 
bidirectional voltage triggered switch. Some characteristics of this 
device include a normal 95 V to 330 V switching point, negative 
resistance range, latching characteristics at turn-on, and a low on-
state voltage drop.
One-cycle surge current capability up to 20 A makes the sidac an 
ideal product for dumping charged capacitors through an inductor 
in order to generate high-voltage pulses. Applications include light 
controls, high-pressure sodium lamp starters, power oscillators, 
and high-voltage power supplies.