Main differences between PD and PT:
1, photocurrent: the output photoelectric flux of PT tube is much larger than that of PD tube. The photoelectric flux of PD tube is microampere, and that of PT tube is milliamp.
2. Dark current: PT tube has large dark current.
3. Response time: The response time of PD tube is very short.
4. Output characteristics: the linearity is good, but the linearity of PT is poor.
5. Size: the size of the PT tube chip is small and the cost is low.
6. Anti-temperature interference: PT tube is easily affected by ambient temperature, and the photocurrent fluctuates greatly.
7. Saturation characteristics: The optical input of PT tube is easily saturated, which is related to its high magnification.
8. Usage: PT tube can be used to reflect and receive light, while PD tube generally receives light directly.
Matters needing attention in the use of both:
1, the electrical parameters of the pipeline are not allowed to exceed its maximum value.
2. The spectral response range of the lamp must match the spectral range of the incident light.
3. During installation, the incident light path must be perpendicular to the light receiving surface of the pipeline to obtain the best response characteristics.
In addition, the interference of external stray light on the pipeline should be avoided, especially when the received optical signal is a constant optical signal.