4 QUADRANT LOGIC LEVEL TRIAC Triode For Alternating Current (TRIAC) 2,400+

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Part RoHS Manufacturer Trigger Device Type Package Style (Meter) Surface Mount Terminal Position Configuration Case Connection Maximum On-state Voltage Package Body Material Maximum DC Gate Trigger Current Non Repetitive Peak On-state Current Terminal Form Package Shape Maximum On-state Current No. of Elements Maximum Leakage Current Repetitive Peak Reverse Voltage Maximum Repetitive Peak Off-state Leakage Current No. of Terminals Sub-Category Maximum Operating Temperature Minimum Operating Temperature Terminal Finish Maximum RMS On-state Current JESD-30 Code Moisture Sensitivity Level (MSL) Maximum DC Gate Trigger Voltage Qualification Repetitive Peak Off-state Voltage Minimum Critical Rate of Rise of Commutation Voltage Minimum Critical Rate of Rise of Off-state Voltage Maximum Holding Current Additional Features JEDEC-95 Code JESD-609 Code Maximum Time At Peak Reflow Temperature (s) Peak Reflow Temperature (C) Reference Standard

T1210T-8FP

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

NOT SPECIFIED

NOT SPECIFIED

BTB04-700A

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

PLASTIC/EPOXY

10 mA

THROUGH-HOLE

RECTANGULAR

1

.75 mA

3

TRIACs

110 Cel

-40 Cel

MATTE TIN

4 A

R-PSFM-T3

2.5 V

Not Qualified

700 V

.00001 V/us

25 mA

SENSITIVE GATE

TO-220AB

e3

BTB08-600TW

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

MAIN TERMINAL 2

PLASTIC/EPOXY

5 mA

THROUGH-HOLE

RECTANGULAR

1

10 uA

3

TRIACs

110 Cel

-40 Cel

MATTE TIN

8 A

R-PSFM-T3

1.5 V

Not Qualified

600 V

1.8 V/us

20 V/us

15 mA

TO-220AB

e3

BTB08-800TWRG

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

MAIN TERMINAL 2

PLASTIC/EPOXY

5 mA

THROUGH-HOLE

RECTANGULAR

1

1 mA

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

8 A

R-PSFM-T3

1.3 V

Not Qualified

800 V

20 V/us

10 mA

TO-220AB

e3

Z0110MA5AL2

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

CYLINDRICAL

NO

BOTTOM

SINGLE

PLASTIC/EPOXY

25 mA

THROUGH-HOLE

RECTANGULAR

1

.5 mA

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

1 A

R-PBCY-T3

1.3 V

Not Qualified

600 V

100 V/us

25 mA

SENSITIVE GATE

TO-92

e3

BTB41-800B

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

MAIN TERMINAL 2

PLASTIC/EPOXY

100 mA

THROUGH-HOLE

RECTANGULAR

1

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

40 A

R-PSFM-T3

1

1.5 V

Not Qualified

800 V

5 V/us

250 V/us

80 mA

e3

T0512DH

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

PLASTIC/EPOXY

50 mA

THROUGH-HOLE

RECTANGULAR

1

2 mA

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

5 A

R-PSFM-T3

2.5 V

Not Qualified

400 V

200 V/us

100 mA

e3

T0810NH

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

PLASTIC/EPOXY

25 mA

THROUGH-HOLE

RECTANGULAR

1

2 mA

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

8 A

R-PSFM-T3

2.5 V

Not Qualified

800 V

200 V/us

50 mA

TO-220AB

e3

BTB04-400D

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

PLASTIC/EPOXY

5 mA

THROUGH-HOLE

RECTANGULAR

1

.75 mA

3

TRIACs

110 Cel

-40 Cel

MATTE TIN

4 A

R-PSFM-T3

2.5 V

Not Qualified

400 V

15 mA

TO-220AB

e3

UL RECOGNIZED

T0609NH

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

PLASTIC/EPOXY

10 mA

THROUGH-HOLE

RECTANGULAR

1

2 mA

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

6 A

R-PSFM-T3

2.5 V

Not Qualified

800 V

50 V/us

25 mA

SENSITIVE GATE

e3

BTB06-600B

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

MAIN TERMINAL 2

PLASTIC/EPOXY

5 mA

THROUGH-HOLE

RECTANGULAR

1

.75 mA

3

TRIACs

110 Cel

-40 Cel

MATTE TIN

6 A

R-PSFM-T3

2.5 V

Not Qualified

600 V

1 V/us

10 V/us

15 mA

TO-220AB

e3

BTB24-600B

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

MAIN TERMINAL 2

PLASTIC/EPOXY

50 mA

THROUGH-HOLE

RECTANGULAR

1

1 mA

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

25 A

R-PSFM-T3

2.5 V

Not Qualified

600 V

500 V/us

50 mA

TO-220AB

e3

BTA04-400A

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

ISOLATED

PLASTIC/EPOXY

10 mA

THROUGH-HOLE

RECTANGULAR

1

.75 mA

3

TRIACs

110 Cel

-40 Cel

MATTE TIN

4 A

R-PSFM-T3

2.5 V

Not Qualified

400 V

.00001 V/us

25 mA

TO-220AB

e3

UL RECOGNIZED

BTA06-400TW

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

ISOLATED

PLASTIC/EPOXY

5 mA

THROUGH-HOLE

RECTANGULAR

1

10 uA

3

TRIACs

110 Cel

-40 Cel

MATTE TIN

6 A

R-PSFM-T3

1.5 V

Not Qualified

400 V

1.3 V/us

20 V/us

15 mA

TO-220AB

e3

BTB10-800BRG

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

MAIN TERMINAL 2

PLASTIC/EPOXY

50 mA

THROUGH-HOLE

RECTANGULAR

1

1 mA

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

10 A

R-PSFM-T3

1.3 V

Not Qualified

800 V

10 V/us

400 V/us

50 mA

TO-220AB

e3

BTB10-800B

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

MAIN TERMINAL 2

PLASTIC/EPOXY

100 mA

THROUGH-HOLE

RECTANGULAR

1

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

10 A

R-PSFM-T3

1.5 V

Not Qualified

800 V

10 V/us

250 V/us

50 mA

TO-220AB

e3

BTB12-400SW

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

PLASTIC/EPOXY

10 mA

THROUGH-HOLE

RECTANGULAR

1

.01 mA

10 uA

3

TRIACs

110 Cel

-40 Cel

MATTE TIN

12 A

R-PSFM-T3

1.5 V

Not Qualified

400 V

50 V/us

25 mA

TO-220AB

e3

BTB16-800C

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

MAIN TERMINAL 2

PLASTIC/EPOXY

25 mA

THROUGH-HOLE

RECTANGULAR

1

2 mA

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

16 A

R-PSFM-T3

1.3 V

Not Qualified

800 V

5 V/us

200 V/us

25 mA

TO-220AB

e3

Z0109SA1AA2

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

CYLINDRICAL

NO

BOTTOM

SINGLE

PLASTIC/EPOXY

10 mA

THROUGH-HOLE

RECTANGULAR

1

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

1 A

R-PBCY-T3

1.3 V

Not Qualified

700 V

2 V/us

50 V/us

10 mA

SENSITIVE GATE

TO-92

e3

Z0410DF

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

IN-LINE

NO

SINGLE

SINGLE

PLASTIC/EPOXY

25 mA

THROUGH-HOLE

RECTANGULAR

1

.2 mA

3

TRIACs

125 Cel

-40 Cel

.95 A

R-PSIP-T3

2 V

Not Qualified

400 V

30 V/us

50 mA

SENSITIVE GATE

NOT SPECIFIED

NOT SPECIFIED

BTA12-800SWRG

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

ISOLATED

PLASTIC/EPOXY

10 mA

THROUGH-HOLE

RECTANGULAR

1

1 mA

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

12 A

R-PSFM-T3

1.3 V

Not Qualified

800 V

40 V/us

15 mA

TO-220AB

e3

BTA10-800BRG

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

ISOLATED

PLASTIC/EPOXY

50 mA

THROUGH-HOLE

RECTANGULAR

1

1 mA

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

10 A

R-PSFM-T3

1.3 V

Not Qualified

800 V

10 V/us

400 V/us

50 mA

TO-220AB

e3

UL RECOGNIZED

BTA06-700T

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

ISOLATED

PLASTIC/EPOXY

5 mA

THROUGH-HOLE

RECTANGULAR

1

.75 mA

3

TRIACs

110 Cel

-40 Cel

MATTE TIN

6 A

R-PSFM-T3

2.5 V

Not Qualified

700 V

1 V/us

10 V/us

15 mA

SENSITIVE GATE

TO-220AB

e3

ACST4-7SH

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

IN-LINE

NO

SINGLE

SINGLE

MAIN TERMINAL 1

PLASTIC/EPOXY

10 mA

THROUGH-HOLE

RECTANGULAR

1

.5 mA

3

TRIACs

125 Cel

-30 Cel

MATTE TIN

4 A

R-PSIP-T3

1 V

Not Qualified

700 V

200 V/us

20 mA

e3

40

260

BTA06-400SW/F5

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

ISOLATED

PLASTIC/EPOXY

10 mA

THROUGH-HOLE

RECTANGULAR

1

10 uA

3

110 Cel

-40 Cel

6 A

R-PSFM-T3

1.5 V

Not Qualified

400 V

50 V/us

25 mA

TO-220AB

Z00607MA5BL2

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

CYLINDRICAL

NO

BOTTOM

SINGLE

PLASTIC/EPOXY

7 mA

THROUGH-HOLE

ROUND

1

.1 mA

3

TRIACs

110 Cel

-40 Cel

TIN

.8 A

O-PBCY-T3

1.3 V

Not Qualified

600 V

1.5 V/us

10 V/us

5 mA

TO-92

e3

Z0405SF1AA2

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

IN-LINE

NO

SINGLE

SINGLE

PLASTIC/EPOXY

5 mA

THROUGH-HOLE

RECTANGULAR

1

.5 mA

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

4 A

R-PSIP-T3

1.3 V

Not Qualified

700 V

1 V/us

20 V/us

5 mA

e3

BTA08-800TW

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

ISOLATED

PLASTIC/EPOXY

5000 mA

THROUGH-HOLE

RECTANGULAR

1

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

8 A

R-PSFM-T3

1.5 V

Not Qualified

800 V

1.8 V/us

20 V/us

15 mA

TO-220AB

e3

BTB12-800C

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

MAIN TERMINAL 2

PLASTIC/EPOXY

25 mA

THROUGH-HOLE

RECTANGULAR

1

10 uA

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

12 A

R-PSFM-T3

1.5 V

Not Qualified

800 V

5 V/us

100 V/us

25 mA

TO-220AB

e3

BTA40-700A

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

UPPER

SINGLE

ISOLATED

PLASTIC/EPOXY

100 mA

350 A

SOLDER LUG

ROUND

1

4 mA

3

TRIACs

125 Cel

-40 Cel

40 A

O-PUFM-D3

2.5 V

Not Qualified

700 V

100 mA

BTA04-700T

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

ISOLATED

PLASTIC/EPOXY

5 mA

THROUGH-HOLE

RECTANGULAR

1

.75 mA

3

TRIACs

110 Cel

-40 Cel

MATTE TIN

4 A

R-PSFM-T3

2.5 V

Not Qualified

700 V

1 V/us

10 V/us

15 mA

TO-220AB

e3

UL RECOGNIZED

BTA06-600SW/F2

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

YES

SINGLE

SINGLE

ISOLATED

PLASTIC/EPOXY

10 mA

GULL WING

RECTANGULAR

1

10 uA

3

110 Cel

-40 Cel

Matte Tin (Sn)

6 A

R-PSFM-G3

1.5 V

Not Qualified

600 V

50 V/us

25 mA

e3

BTA41-700A

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

ISOLATED

PLASTIC/EPOXY

100 mA

THROUGH-HOLE

RECTANGULAR

1

4 mA

3

TRIACs

125 Cel

-40 Cel

40 A

R-PSFM-T3

2.5 V

Not Qualified

700 V

5 V/us

150 V/us

100 mA

Z0410NF0AA2

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

IN-LINE

NO

SINGLE

SINGLE

PLASTIC/EPOXY

25 mA

THROUGH-HOLE

RECTANGULAR

1

.5 mA

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

4 A

R-PSIP-T3

1.3 V

Not Qualified

800 V

5 V/us

200 V/us

25 mA

e3

Z0410DE

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

PLASTIC/EPOXY

25 mA

THROUGH-HOLE

RECTANGULAR

1

.2 mA

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

4 A

R-PSFM-T3

2 V

Not Qualified

400 V

30 V/us

50 mA

TO-202

e3

T405-700T

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

MAIN TERMINAL 2

PLASTIC/EPOXY

5 mA

THROUGH-HOLE

RECTANGULAR

1

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

4 A

R-PSFM-T3

Not Qualified

700 V

SENSITIVE GATE

TO-220AB

e3

BTA08-600SRG

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

NO

10 mA

.5 mA

TRIACs

110 Cel

-40 Cel

8 A

2.5 V

600 V

10 V/us

500 V/us

25 mA

NOT SPECIFIED

NOT SPECIFIED

Z0109MA2AL2

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

CYLINDRICAL

NO

BOTTOM

SINGLE

PLASTIC/EPOXY

10 mA

THROUGH-HOLE

RECTANGULAR

1

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

1 A

R-PBCY-T3

1.3 V

Not Qualified

600 V

2 V/us

50 V/us

10 mA

SENSITIVE GATE

TO-92

e3

Z0410ME

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

PLASTIC/EPOXY

25 mA

THROUGH-HOLE

RECTANGULAR

1

.2 mA

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

4 A

R-PSFM-T3

2 V

Not Qualified

600 V

30 V/us

50 mA

TO-202

e3

BTA04-600A

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

ISOLATED

PLASTIC/EPOXY

10 mA

THROUGH-HOLE

RECTANGULAR

1

.75 mA

3

TRIACs

110 Cel

-40 Cel

MATTE TIN

4 A

R-PSFM-T3

2.5 V

Not Qualified

600 V

.00001 V/us

25 mA

TO-220AB

e3

UL RECOGNIZED

BTA06-400C

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

ISOLATED

PLASTIC/EPOXY

25 mA

THROUGH-HOLE

RECTANGULAR

1

.5 mA

3

TRIACs

MATTE TIN

6 A

R-PSFM-T3

Not Qualified

400 V

5 V/us

50 V/us

50 mA

TO-220AB

e3

BTA06-800TWRG

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

ISOLATED

PLASTIC/EPOXY

5 mA

THROUGH-HOLE

RECTANGULAR

1

1 mA

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

6 A

R-PSFM-T3

1.3 V

Not Qualified

800 V

20 V/us

10 mA

TO-220AB

e3

UL RECOGNIZED

T405-800H

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

IN-LINE

NO

SINGLE

SINGLE

MAIN TERMINAL 2

PLASTIC/EPOXY

5 mA

THROUGH-HOLE

RECTANGULAR

1

.005 mA

3

TRIACs

125 Cel

-40 Cel

TIN

4 A

R-PSIP-T3

1.3 V

Not Qualified

800 V

20 V/us

10 mA

e3

BTA06-400SW

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

ISOLATED

PLASTIC/EPOXY

10 mA

THROUGH-HOLE

RECTANGULAR

1

10 uA

3

TRIACs

110 Cel

-40 Cel

MATTE TIN

6 A

R-PSFM-T3

1.5 V

Not Qualified

400 V

2.7 V/us

50 V/us

25 mA

TO-220AB

e3

BTA08-600B

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

ISOLATED

PLASTIC/EPOXY

50 mA

THROUGH-HOLE

RECTANGULAR

1

.5 mA

3

TRIACs

110 Cel

-40 Cel

MATTE TIN

8 A

R-PSFM-T3

2.5 V

Not Qualified

600 V

10 V/us

500 V/us

50 mA

TO-220AB

e3

BTA06-700TW/F2

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

YES

SINGLE

SINGLE

ISOLATED

PLASTIC/EPOXY

5 mA

GULL WING

RECTANGULAR

1

10 uA

3

110 Cel

-40 Cel

6 A

R-PSFM-G3

1.5 V

Not Qualified

700 V

20 V/us

15 mA

BTA06-400B

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

ISOLATED

PLASTIC/EPOXY

50 mA

THROUGH-HOLE

RECTANGULAR

1

.5 mA

3

TRIACs

110 Cel

-40 Cel

MATTE TIN

6 A

R-PSFM-T3

2.5 V

Not Qualified

400 V

10 V/us

100 V/us

50 mA

TO-220AB

e3

BTB12-800TWRG

STMicroelectronics

4 QUADRANT LOGIC LEVEL TRIAC

FLANGE MOUNT

NO

SINGLE

SINGLE

MAIN TERMINAL 2

PLASTIC/EPOXY

5 mA

THROUGH-HOLE

RECTANGULAR

1

.005 mA

3

TRIACs

125 Cel

-40 Cel

MATTE TIN

12 A

R-PSFM-T3

1.3 V

Not Qualified

800 V

20 V/us

10 mA

TO-220AB

e3

Triode For Alternating Current (TRIAC)

A Triode for Alternating Current (TRIAC) is a semiconductor device that is used to control the flow of electrical current in AC circuits. It is a bidirectional device that can conduct current in both directions, making it useful for AC power control applications.

TRIACs consist of a bidirectional switching element that allows for the control of AC current in both directions. They are typically used in applications where AC voltage needs to be controlled, such as in lighting control, motor speed control, and power supplies.

TRIACs work by applying a small current or voltage to the gate terminal, which allows current to flow through the device. Once the current reaches a certain level, the TRIAC turns on and conducts current in both directions until the current drops below a certain threshold, at which point the TRIAC turns off.

TRIACs are commonly used in conjunction with other components such as capacitors, inductors, and diodes to form complete electronic circuits. They are often used in power control circuits that require precise control of AC voltage or current.