SMARTLED® Series, Phototransistors

The phototransistor family consists of discrete light-sensitive components that exhibit similar behavior to bipolar transistors. However, unlike bipolar transistors that rely on an electrical current applied through a device terminal, phototransistors utilize incident light to induce conduction. Phototransistors offer several advantages compared to photodiodes. One notable advantage is that they generally generate a larger output current in response to the same intensity of incident light. This higher output current makes phototransistors more suitable for applications where a higher signal strength is desired. On the other hand, phototransistors have a slower response time to changes in light intensity compared to photodiodes. This means that they may not be as well-suited for high-speed operations that require rapid detection and response to light variations. Due to their simpler application and higher output current capabilities, phototransistors are often preferred in situations where simplicity and signal strength are more critical than speed. They find common use in applications such as ambient light sensing, optical switches, encoders, and remote control systems. It is important to consider the specific requirements of a given application when selecting between phototransistors and photodiodes, taking into account factors such as sensitivity, response time, and signal strength. By understanding the unique characteristics and trade-offs of phototransistors, engineers can make informed decisions to optimize their designs for different light sensing scenarios.