This Product Selection Guide contains information to help select products in the Optical Sensors - Phototransistors category on DigiKey.com
Products in the phototransistor family are discrete light sensitive components which behave in similar fashion to a bipolar transistor, but use incident light instead of an electrical current applied through a device terminal to cause the device to conduct. Compared to photodiodes, phototransistors generally produce a much larger output current for the same intensity of incident light, though are slower to respond to changes in light intensity. These differences result in phototransistors being simpler to apply, but less useful for high speed operation.
SelectionCharacteristics
Specifications to determine which phototransistor is right for your application.
Voltage – Collector Emitter Breakdown (Max): The maximum voltage between the collector and emitter of the transistor that can be tolerated by the transistor. Exceeding this voltage will damage or destroy the transistor.
Current – Collector (Ic) (Max): The maximum current than can run through the collector of the transistor. Exceeding this current will damage or destroy the transistor.
Current – Dark (Id) (Max): Current conducted by a device under conditions of zero illumination and a specified applied voltage. Strongly dependent on device temperature.
Wavelength: This is the wavelength at which peak sensitivity is reached.
Viewing Angle: The angle of optimum sensitivity of light detection.
Power – Max: Maximum power dissipation of the sensor. Typically measured in free air at a specific temperature.
Mounting Type: Indicates how the device is attached.
Orientation: Identifies the side of the sensor that receives the light input.
Operating Temperature: Recommended operating temperature, typically given in a range or as a maximum. Exceeding these temperatures may affect performance or damage the device and other system components.
Package/Case: Indicates the type of protective case used on an electronic component to allow easy handling, installation, and protection. This selection was determined to be the closest industry standard applicable to the suppliers device packaging. Typically it is best to check the actual dimensions from the datasheet rather than depend on this terminology when designing your circuit.
ProductExamples
| MFR PART # | APA3010P3BT-GX |
|---|---|
| DIGI-KEY PART # | 754-1841-2-ND - Tape & Reel (TR) |
| MANUFACTURER | Kingbright |
| DESCRIPTION | Phototransistors Side View 2-SMD, No Lead |
| DATASHEET | Click Here |
| MFR PART # | VEMT2020X01 |
|---|---|
| DIGI-KEY PART # | VEMT2020X01TR-ND - Tape & Reel (TR) |
| MANUFACTURER | Vishay Semiconductor Opto Division |
| DESCRIPTION | Phototransistors 860nm Top View 2-SMD, Gull Wing |
| DATASHEET | Click Here |
| MFR PART # | OP550B |
|---|---|
| DIGI-KEY PART # | 365-1071-ND |
| MANUFACTURER | TT Electronics/Optek Technology |
| DESCRIPTION | Phototransistors 935nm Side View Radial |
| DATASHEET | Click Here |
| MFR PART # | OP644SL |
|---|---|
| DIGI-KEY PART # | 365-1078-ND |
| MANUFACTURER | TT Electronics/Optek Technology |
| DESCRIPTION | SENSOR PHOTO 890NM TOP VIEW PILL |
| DATASHEET | Click Here |
| MFR PART # | OP830SL |
|---|---|
| DIGI-KEY PART # | 365-1619-ND |
| MANUFACTURER | TT Electronics/Optek Technology |
| DESCRIPTION | Phototransistors Top View TO-206AA, TO-18-3 Metal Can |
| DATASHEET | Click Here |
Schematic Symbol
Phototransistor schematic symbols courtesy of Scheme-It please use the link for more information and symbols.
MediaLinks
Articles
The Basics of Photodiodes and Phototransistors
Implementation of Photodiodes & Phototransistors
Blogs
How to Use a Phototransistor with an Arduino
TechForum
TechForum posts on Phototransistors