In fact, it is determined by the common circuit structure. When the circuit is low, the circuit tends to have a lower loop impedance at a higher level, while the lower impedance means more anti-interference capability. Combine practical examples with a practical example to deepen your impression:
Some of our classmates may have learned such a PCB layout rule----in the case of conditional permission, the active-high line should be shortened as much as possible, and the active-low line should be extended as much as possible----this one The basis of the existence of the rule is that the loop impedance is relatively low based on the low level, and the anti-interference ability is relatively strong.
For example, the OC or OD circuit needs to control a level through the on and off of this switch. In the case of a pull-up resistor, the switch is turned on, and it is low; the switch is turned off, and it is high. In this way, in order to prevent the circuit from being out of control, it is still an effective level, then of course it is more effective to be "insecure". Structurally, like the OC circuit, since the collector is more difficult to break down, it is less likely to be damaged.
For other totem pole output circuits, although 0 and 1 have the same risk, there are still people in the application who are willing to add a pull-up resistor to achieve OC or OD output. As for why you don't use pull-down resistors and pull-up resistors, you can analyze them.
Another aspect is the OC or OD output circuit, which uses an energy-saving effect after using a pull-up resistor. Because it is turned off, it has almost zero current when it gets high.
An optical dome is a concentric window with two spheres. It can be understood as an optical window of a curved moon. Optical dome is used for deep-sea submersible, deep-sea equipment monitoring and underwater robot. At the same time, optical dome is widely used in meteorological industry. It can be used as an optical protective cover to protect the total radiation sensor, the sensor for solar total radiation observation, the net radiation sensor, the PTZ camera, and other precision instruments and equipment used in harsh environments.
Our company produces optical ball covers made of optical glass, fused quartz, silicon and other materials, and can produce optical hemispherical ball covers with a maximum diameter of 300mm. For an ideal optical spherical cover, the convex radius is equal to the sum of the thickness and concave radius. The thickness change at different points on the two surfaces is the main index to measure the accuracy of the spherical cover. Sometimes we call it the congruent thickness and concentricity of the optical spherical cover. For the optical ball cover with size less than 100mm, our concentricity can be controlled within 0.02mm.
Optical Dome
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