Phototransistors are solid state light detectors that possess internal gain. This makes them much more sensitive than photodiodes of comparably sized area. These devices can be used to provide either an analog or digital output signal. This family of detectors offers the following general characteristics and features:
IRED's are solid state light sources which emit light in the near-IR part of the spectrum. Because they emit at wavelengths which provide a close match to the peak spectral response of silicon photodetectors both GaAs and GaAlAs LEDs are often used with phototransistors and photodarlingtons. Key characteristics and features of these light sources include:
Phototransistors can be used as ambient light detectors. When used with a controllable light source, typically and LED, they are often employed as the detector element for optoisolators and transmissive or reflective optical switches. Typical configurations include:
Optoisolator The optoisolator is similar to a transformer in that the output is electrically isolated from the input. |
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Optical Switch An object is detected when it enters the gap of the optical switch and blocks the light path between the emitter and detector. |
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Retro Sensor The retrosensor detects the presence of an object by generating light and then looking for its reflectance off of the object to be sensed. |
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Phototransistors and IREDs have been used in the following applications. | |
Computer/Business Equipment
Industrial
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Consumer
Medical
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Fundamental Circuit Approaches | |
Basic Circuits |
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More Output Current Capability |
More Voltage Switching
Capability |
Reducing Dark Current |
For a copy of the original data sheet, or to send comments,
E-Mail us at: eod@egginc.com
Or call us at 1-800-775-OPTO (6786).
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