Vishay Semiconductor Opto Division(8828)

Compare Image Name Manufacturer Pricing(USD) Quantity Weight(Kg) Size(LxWxH) Part Status Mount Mounting Type Operating Temperature Packaging Moisture Sensitivity Level (MSL) Max Operating Temperature Min Operating Temperature Input Type RoHS Status Published Datasheet Voltage - Rated DC Package / Case Length Input Current Height Width Lead Free Shape Factory Lead Time Approval Agency REACH SVHC Number of Pins Lead Pitch Pbfree Code Orientation ECCN Code Additional Feature Contact Plating Radiation Hardening Reach Compliance Code HTS Code Number of Functions Nominal Supply Current JESD-609 Code Terminal Finish Voltage Surface Mount Max Power Dissipation Voltage - Supply Base Part Number Number of Channels Power Dissipation Response Time Number of Elements Subcategory Supplier Device Package Data Rate Max Output Voltage Output Voltage Output Current Forward Current Forward Voltage Output Type Max Input Current Optoelectronic Device Type Forward Current-Max Mounting Feature Viewing Angle Lens Style Rise Time Fall Time (Typ) Configuration Row Spacing Breakdown Voltage Voltage - Isolation Reverse Breakdown Voltage Diode Type Max Reverse Voltage (DC) Collector Emitter Breakdown Voltage Collector Emitter Saturation Voltage Collector Emitter Voltage (VCEO) Max Collector Current Voltage - Forward (Vf) (Typ) Rise / Fall Time (Typ) Current - DC Forward (If) (Max) Reverse Voltage (DC) Output Current per Channel Current Transfer Ratio Semiconductor Material Standards Wavelength Current - Output / Channel Dark Current Size Fiber Optic Device Type Infrared Range Voltage - Output (Max) Dark Current-Max Idle Current, Typ @ 25°C Link Range, Low Power Shutdown Voltage - DC Reverse (Vr) (Max) Spectral Range Active Area Current - Dark (Typ) Light Current-Nom Current Transfer Ratio (Min) Current Transfer Ratio (Max) Turn On / Turn Off Time (Typ) Vce Saturation (Max)
TFDU5307-TT3 TFDU5307-TT3 Vishay Semiconductor Opto Division
RFQ

Min: 1

Mult: 1

download -30°C~85°C Tape & Reel (TR) 4 (72 Hours) ROHS3 Compliant 2007 /files/vishaysemiconductoroptodivision-tfdu5307tr1-datasheets-1884.pdf 8.5mm No SVHC 8 yes Top View unknown 1.1mA e3 Matte Tin (Sn) YES 2.7V~5.5V Fiber Optic Transceivers 1.152Mbs (MIR) SURFACE MOUNT IrPHY 1.4 900 nm 8.5mmx2.9mmx2.5mm TRANSCEIVER 550μA 70cm Yes
TEMD5110X01 TEMD5110X01 Vishay Semiconductor Opto Division
RFQ

Min: 1

Mult: 1

download PCB, Surface Mount Surface Mount -40°C~100°C Tape & Reel (TR) 4 (72 Hours) 100°C -40°C ROHS3 Compliant 2011 /files/vishaysemiconductoroptodivision-temd5110x01-datasheets-9887.pdf 4-SMD, No Lead 4.2mm 1.08mm 5mm Lead Free 7 Weeks Unknown 2 No 215mW 215mW 100ns 50mA 1.3V 130° 100ns 100 ns 60V PIN 60V 60V 940nm 2nA 60V 790nm ~ 1050nm 7.5mm2 2nA
TEFD4300 TEFD4300 Vishay Semiconductor Opto Division
RFQ

Min: 1

Mult: 1

download Through Hole Through Hole -40°C~100°C Bulk 1 (Unlimited) 100°C -40°C ROHS3 Compliant 2012 /files/vishaysemiconductoroptodivision-tefd4300-datasheets-0612.pdf Radial Lead Free 32 Weeks Unknown 2 No 215mW 215mW 100ns 50mA 1V 40° Clear 100ns 100 ns 60V PIN 10V 60V 950nm 150pA 10V 350nm ~ 1120nm 150pA
VBP104FAS VBP104FAS Vishay Semiconductor Opto Division
RFQ

Min: 1

Mult: 1

download PCB, Surface Mount Surface Mount -40°C~100°C Digi-Reel® 3 (168 Hours) ROHS3 Compliant 2009 /files/vishaysemiconductoroptodivision-vbp104fas-datasheets-0409.pdf 2-SMD, Gull Wing 4.4mm 1.2mm 3.9mm Lead Free SQUARE 13 Weeks Unknown 2 yes DAY LIGHT FILTER, HIGH SENSITIVITY No 8541.40.60.50 1 e3 Matte Tin (Sn) 215mW 215mW Photo Diodes 50mA 1.3V 130° 100ns 100 ns SINGLE 60V 60V PIN 60V 60V Silicon 950nm 2nA YES 780nm ~ 1050nm 4.4mm2 2nA 0.035mA
VEMD5510C VEMD5510C Vishay Semiconductor Opto Division
RFQ

Min: 1

Mult: 1

download Surface Mount -40°C~100°C Tape & Reel (TR) 4 (72 Hours) ROHS3 Compliant 2018 /files/vishaysemiconductoroptodivision-vemd5510c-datasheets-1705.pdf 4-SMD, No Lead Exposed Pad 9 Weeks 70ns 130° PIN 550nm 440nm ~ 700nm 7.5mm2 200pA
VEMD5510CF VEMD5510CF Vishay Semiconductor Opto Division
RFQ

Min: 1

Mult: 1

download Surface Mount -40°C~100°C Tape & Reel (TR) 2A (4 Weeks) ROHS3 Compliant 2018 /files/vishaysemiconductoroptodivision-vemd5510cf-datasheets-4894.pdf 4-SMD, No Lead Exposed Pad 9 Weeks 70ns 130° PIN 540nm 440nm ~ 620nm 7.5mm2 200pA
CNY17F-3X001 CNY17F-3X001 Vishay Semiconductor Opto Division $0.56
RFQ

Min: 1

Mult: 1

download Through Hole Through Hole -55°C~110°C Tube 1 (Unlimited) 100°C -55°C DC ROHS3 Compliant 1995 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-cny17f3x001-datasheets-4554.pdf 6-DIP (0.300, 7.62mm) 60mA 11 Weeks Unknown 6 No 150mW 1 150mW 1 6-DIP 70V 70V 60mA 1.65V Transistor 60mA 3μs 14 μs 5000Vrms 6V 400mV 70V 100mA 1.39V 2μs 2μs 60mA 50mA 50mA 70V 100% @ 10mA 200% @ 10mA 3μs, 2.3μs 400mV
ILQ615-1 ILQ615-1 Vishay Semiconductor Opto Division $2.69
RFQ

Min: 1

Mult: 1

download Through Hole Through Hole -55°C~100°C Tube 1 (Unlimited) 100°C -55°C DC ROHS3 Compliant 2011 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-ilq6151-datasheets-4795.pdf 1.15V 16-DIP (0.300, 7.62mm) 10mA 6 Weeks Unknown 16 No 500mW 4 500mW 4 16-DIP 70V 70V 60mA 1.3V Transistor 60mA 5300Vrms 6V 70V 50mA 1.15V 2μs 2μs 60mA 6V 50mA 50mA 70V 40% @ 10mA 80% @ 10mA 3μs, 2.3μs
VOL628A VOL628A Vishay Semiconductor Opto Division
RFQ

Min: 1

Mult: 1

download Surface Mount Surface Mount -55°C~110°C Tape & Reel (TR) 1 (Unlimited) 110°C -55°C AC, DC ROHS3 Compliant 1995 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-vol628a-datasheets-5235.pdf 4-SMD, Gull Wing 60mA 6 Weeks Unknown 4 150mW 1 4-LSOP (2.54mm) 80V 80V 60mA 1.16V Transistor 130mA 3.5μs 5 μs 5000Vrms 400mV 400mV 100mA 1.16V 3.5μs 5μs 60mA 50mA 50mA 80V 50% @ 1mA 600% @ 1mA 6μs, 5.5μs 400mV
VO615A-7 VO615A-7 Vishay Semiconductor Opto Division $0.37
RFQ

Min: 1

Mult: 1

download Through Hole Through Hole -55°C~110°C Tube 1 (Unlimited) 110°C -55°C DC ROHS3 Compliant 1995 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-vo615a4x018t-datasheets-4982.pdf 4-DIP (0.300, 7.62mm) 60mA 14 Weeks Unknown 4 No 70mW 1 70mW 1 4-DIP 70V 70V 60mA 1.43V Transistor 60mA 3μs 4.7 μs 5000Vrms 6V 300mV 70V 50mA 1.43V 3μs 4.7μs 60mA 50mA 50mA 70V 80% @ 5mA 160% @ 5mA 6μs, 5μs 300mV
VO615A-4X006 VO615A-4X006 Vishay Semiconductor Opto Division $0.35
RFQ

Min: 1

Mult: 1

download Through Hole Through Hole -55°C~110°C Tube 1 (Unlimited) DC ROHS3 Compliant 1995 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-vo615a4x018t-datasheets-4982.pdf 4-DIP (0.400, 10.16mm) 14 Weeks 4 EAR99 UL RECOGNIZED No 70mW 1 70mW 1 70V 70V 60mA Transistor 60mA SINGLE 5000Vrms 6V 300mV 70V 50mA 1.43V 3μs 4.7μs 50mA 160% @ 10mA 320% @ 10mA 6μs, 5μs
VO618A-2 VO618A-2 Vishay Semiconductor Opto Division
RFQ

Min: 1

Mult: 1

download Through Hole Through Hole -55°C~110°C Tube 1 (Unlimited) 110°C -55°C DC ROHS3 Compliant 1995 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-vo618a2-datasheets-5667.pdf 4-DIP (0.300, 7.62mm) 60mA 11 Weeks Unknown 4 No 150mW 1 150mW 1 4-DIP 80V 80V 60mA 1.1V Transistor 60mA 3μs 14 μs 5300Vrms 6V 400mV 80V 50mA 1.1V 2μs 2μs 60mA 50mA 50mA 80V 63% @ 1mA 125% @ 1mA 3μs, 2.3μs 400mV
SFH617A-1 SFH617A-1 Vishay Semiconductor Opto Division $0.67
RFQ

Min: 1

Mult: 1

download Through Hole Through Hole -55°C~110°C Tube 1 (Unlimited) 110°C -55°C DC ROHS3 Compliant 1995 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-sfh617a3x006-datasheets-4512.pdf 4-DIP (0.300, 7.62mm) 60mA 11 Weeks No SVHC 4 Tin No 150mW 1 400mW 1 4-DIP 70V 70V 60mA 1.65V Transistor 60mA 5300Vrms 6V 400mV 70V 100mA 1.35V 2μs 2μs 60mA 50mA 50mA 70V 40% @ 10mA 80% @ 10mA 3μs, 2.3μs 400mV
SFH610A-3X016 SFH610A-3X016 Vishay Semiconductor Opto Division
RFQ

Min: 1

Mult: 1

download Through Hole Through Hole -55°C~100°C Tube 1 (Unlimited) 100°C -55°C DC ROHS3 Compliant 1995 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-vo3120x007t-datasheets-8474.pdf 4-DIP (0.400, 10.16mm) 6 Weeks 4 No 150mW 1 150mW 1 4-DIP 70V 60mA 1.25V Transistor 60mA 5300Vrms 6V 400mV 70V 100mA 1.25V 2μs 2μs 60mA 50mA 50mA 70V 100% @ 10mA 200% @ 10mA 3μs, 2.3μs 400mV
6N135-X007 6N135-X007 Vishay Semiconductor Opto Division $1.27
RFQ

Min: 1

Mult: 1

download Surface Mount, Through Hole Through Hole -55°C~100°C Tube 1 (Unlimited) 100°C -55°C DC ROHS3 Compliant 2015 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-6n136x007-datasheets-4789.pdf 8-DIP (0.300, 7.62mm) 6 Weeks 8 No 100mW 6N135 1 100mW 1 8-DIP 1 Mbps 15V 400mV 8mA 16mA 1.33V Transistor with Base 25mA 5ns 5 ns 5300Vrms 5V 8mA 1.33V 25mA 5V 8mA 16 % 8mA 15V 7% @ 16mA 300ns, 300ns
SFH6345-X001 SFH6345-X001 Vishay Semiconductor Opto Division
RFQ

Min: 1

Mult: 1

download Through Hole Through Hole -55°C~100°C Tube 1 (Unlimited) DC ROHS3 Compliant 1995 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-sfh6345x001-datasheets-6347.pdf 8-DIP (0.300, 7.62mm) 6 Weeks 8 UL RECOGNIZED, VDE APPROVED, TTL COMPATIBLE, OPEN COLLECTOR OUTPUT No e3 Tin (Sn) 100mW 1 100mW 1 1 MBps 25V 25mA Transistor 25mA LOGIC IC OUTPUT OPTOCOUPLER SINGLE 5300Vrms 3V 400mV 400mV 1.33V 8mA 30 % 19% @ 16mA 300ns, 300ns
ILD610-3 ILD610-3 Vishay Semiconductor Opto Division $2.08
RFQ

Min: 1

Mult: 1

download Through Hole Through Hole -55°C~100°C Tube 1 (Unlimited) 100°C -55°C DC ROHS3 Compliant 2012 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-ild6103-datasheets-6505.pdf 8-DIP (0.300, 7.62mm) 60mA 6 Weeks 8 No 150mW 2 150mW 2 8-DIP 70V 90V 60mA 1.25V Transistor 60mA 5300Vrms 6V 400mV 70V 100mA 1.25V 2.9μs 3.1μs 60mA 50mA 50mA 70V 100% @ 10mA 200% @ 10mA 3.6μs, 3.7μs 400mV
IL300-DEFG-X006 IL300-DEFG-X006 Vishay Semiconductor Opto Division
RFQ

Min: 1

Mult: 1

download Through Hole Through Hole -55°C~100°C Tube 1 (Unlimited) 100°C -55°C DC ROHS3 Compliant 2014 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-il300defgx016-datasheets-4936.pdf 8-DIP (0.400, 10.16mm) 6 Weeks 8 No 210mW 1 210mW 1 8-DIP 500mV 60mA 1.25V Photovoltaic, Linearized 60mA 1.75μs 1.75 μs 5300Vrms 5V 1.25V 1μs 1μs 60mA 5V 1.1 % 70μA Typ 500mV
VOM617A-8T VOM617A-8T Vishay Semiconductor Opto Division
RFQ

Min: 1

Mult: 1

download Surface Mount Surface Mount -55°C~110°C Tape & Reel (TR) 1 (Unlimited) DC ROHS3 Compliant 1995 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-vom617a8t-datasheets-7079.pdf 4-SMD, Gull Wing 60mA 8 Weeks 4 EAR99 UL APPROVED No 170mW 1 1 80V Transistor 60mA 0.06A SINGLE 3750Vrms 400mV 80V 100mA 1.1V 3μs 3μs 100mA 50mA 130% @ 5mA 260% @ 5mA 6μs, 4μs
TCLT1007 TCLT1007 Vishay Semiconductor Opto Division
RFQ

Min: 1

Mult: 1

download Surface Mount Surface Mount -55°C~100°C Tape & Reel (TR) 1 (Unlimited) DC ROHS3 Compliant https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-tclt1004-datasheets-4892.pdf 70V 4-SMD, Gull Wing 50mA 7.5mm Lead Free 6 Weeks No SVHC 4 10.2mm EAR99 UL RECOGNIZED Tin No 250mW 1 250mW 1 70V 70V 60mA Transistor 60mA 6μs 4.7 μs SINGLE 2.54 mm 5000Vrms 6V 70V 300mV 70V 50mA 1.25V 3μs 4.7μs 50mA 80% @ 5mA 160% @ 5mA 6μs, 5μs 300mV
TCLD1000 TCLD1000 Vishay Semiconductor Opto Division
RFQ

Min: 1

Mult: 1

download PCB, Surface Mount Surface Mount -55°C~100°C Cut Tape (CT) 1 (Unlimited) 100°C -55°C DC ROHS3 Compliant 2004 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-tcld1000-datasheets-7917.pdf 1.25V 4-SMD, Gull Wing 60mA 7.5mm Lead Free 6 Weeks Unknown 4 250mW 1 250mW 1 4-LSOP (2.54mm) 35V 35V 80mA 60mA 1.6V Darlington 60mA 300s 5000Vrms 6V 1V 35V 80mA 1.1V 300μs - 60mA 6V 80mA 800 % 80mA 35V 600% @ 1mA -, 250μs 1V
TCLT1018 TCLT1018 Vishay Semiconductor Opto Division $1.63
RFQ

Min: 1

Mult: 1

download Surface Mount Surface Mount -55°C~110°C Tape & Reel (TR) 1 (Unlimited) 110°C -55°C DC ROHS3 Compliant 2016 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-tclt1013-datasheets-4990.pdf 4-SMD, Gull Wing 6 Weeks 4 No 250mW 1 250mW 1 4-LSOP (2.54mm) 70V 60mA 1.25V Transistor 60mA 5000Vrms 6V 300mV 70V 50mA 1.25V 3μs 4.7μs 60mA 50mA 50mA 70V 130% @ 5mA 260% @ 5mA 6μs, 5μs 300mV
IL208AT IL208AT Vishay Semiconductor Opto Division $0.94
RFQ

Min: 1

Mult: 1

download Surface Mount Surface Mount -55°C~100°C Tape & Reel (TR) 1 (Unlimited) 100°C -55°C DC ROHS3 Compliant 2001 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-il207at-datasheets-8915.pdf 1.3V 8-SOIC (0.154, 3.90mm Width) 60mA Lead Free 6 Weeks Unknown 8 Tin No 240mW 1 240mW 1 8-SOIC 70V 70V 60mA 1.5V Transistor with Base 60mA 4000Vrms 400mV 70V 100mA 1.3V 60mA 70V 100% @ 10mA 320% @ 10mA 3μs, 3μs 400mV
SFH6106-1X001T SFH6106-1X001T Vishay Semiconductor Opto Division $0.83
RFQ

Min: 1

Mult: 1

download Surface Mount, Through Hole Surface Mount -55°C~100°C Tape & Reel (TR) 1 (Unlimited) DC ROHS3 Compliant https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-sfh61064-datasheets-4576.pdf 4-SMD, Gull Wing Lead Free 6 Weeks 4 yes EAR99 UL APPROVED, VDE APPROVED No e3 Matte Tin (Sn) 6V 150mW 1 150mW 1 70V 60mA Transistor 60mA 2μs 11 μs SINGLE 5300Vrms 6V 400mV 70V 100mA 1.25V 2μs 2μs 50mA 50nA 40% @ 10mA 80% @ 10mA 3μs, 2.3μs
ILQ615-4 ILQ615-4 Vishay Semiconductor Opto Division $2.33
RFQ

Min: 1

Mult: 1

download Through Hole Through Hole -55°C~100°C Tube 1 (Unlimited) 100°C -55°C DC ROHS3 Compliant 2001 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-ilq6151-datasheets-4795.pdf 1.15V 16-DIP (0.300, 7.62mm) 10mA Lead Free 6 Weeks Unknown 16 No 500mW 4 500mW 4 16-DIP 70V 70V 60mA 1.3V Transistor 60mA 4.6μs 15 μs 5300Vrms 6V 70V 50mA 1.15V 2μs 2μs 60mA 50mA 50mA 70V 160% @ 320mA 320% @ 10mA 3μs, 2.3μs
TCLT1109 TCLT1109 Vishay Semiconductor Opto Division
RFQ

Min: 1

Mult: 1

download Surface Mount Surface Mount -55°C~100°C Tape & Reel (TR) 1 (Unlimited) DC ROHS3 Compliant 2004 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-tclt1102-datasheets-4901.pdf 1.25V 6-SOIC (0.295, 7.50mm Width), 5 Leads 50mA 7.5mm 15 Weeks Unknown 5 EAR99 UL RECOGNIZED No 250mW 1 250mW 1 70V 60mA Transistor with Base 60mA TRANSISTOR OUTPUT OPTOCOUPLER 3μs 4.7 μs SINGLE 5000Vrms 6V 300mV 70V 50mA 3μs 4.7μs 50mA 80V 200% @ 5mA 400% @ 5mA 6μs, 5μs
K814P K814P Vishay Semiconductor Opto Division $0.11
RFQ

Min: 1

Mult: 1

download Through Hole Through Hole -40°C~100°C Tube 1 (Unlimited) AC, DC ROHS3 Compliant 2016 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-k814p-datasheets-1054.pdf 1.25V 4-DIP (0.300, 7.62mm) 50mA Lead Free 6 Weeks Unknown 4 UL RECOGNIZED No 250mW 1 250mW 1 70V 70V 60mA Transistor 60mA 3μs 4.7 μs SINGLE 5000Vrms 300mV 70V 50mA 3μs 4.7μs 50mA 20% @ 5mA 300% @ 5mA 6μs, 5μs
SFH618A-5 SFH618A-5 Vishay Semiconductor Opto Division
RFQ

Min: 1

Mult: 1

download Through Hole Through Hole -55°C~100°C Tube 1 (Unlimited) 100°C -55°C DC ROHS3 Compliant 2011 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-sfh618a3x017t-datasheets-5215.pdf 1.1V 4-DIP (0.300, 7.62mm) 4.83mm 60mA 3.81mm 6.81mm Lead Free 6 Weeks No SVHC 4 No 150mW 1 150mW 1 4-DIP 55V 55V 60mA 1.5V Transistor 60mA 5300Vrms 6V 400mV 55V 100mA 1.1V 3.5μs 5μs 60mA 6V 50mA 50mA 55V 250% @ 1mA 500% @ 1mA 6μs, 5.5μs 400mV
CNY117-2X006 CNY117-2X006 Vishay Semiconductor Opto Division $0.81
RFQ

Min: 1

Mult: 1

download Through Hole Through Hole -55°C~110°C Tube 1 (Unlimited) DC ROHS3 Compliant 2016 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-cny1174-datasheets-5610.pdf 6-DIP (0.400, 10.16mm) 11 Weeks 6 EAR99 No 150mW 1 70V Transistor with Base 60mA TRANSISTOR OUTPUT OPTOCOUPLER 5000Vrms 400mV 70V 100mA 1.39V 2μs 2μs 50mA 70V 63% @ 10mA 125% @ 10mA 3μs, 2.3μs
IL250 IL250 Vishay Semiconductor Opto Division $0.18
RFQ

Min: 1

Mult: 1

download Through Hole Through Hole -55°C~100°C Tube 1 (Unlimited) 100°C -55°C AC, DC ROHS3 Compliant 2005 https://pdf.utmel.com/r/datasheets/vishaysemiconductoroptodivision-il252-datasheets-4678.pdf 1.2V 6-DIP (0.300, 7.62mm) 60mA Lead Free 6 Weeks UL Unknown 6 No 400mW 1 250mW 1 6-DIP 30V 50V 60mA 1.5V Transistor with Base 60mA 5300Vrms 30V 400mV 30V 1.2V 60mA 30V 50% @ 10mA 400mV

In Stock

Please send RFQ , we will respond immediately.