Sunday, January 16, 2011
【 Weak current College 】 light ouheqi main parameters 】
(1) of the input parameter is the input-side of the main parameters of the light-emitting devices, essentially refers to the light-emitting diode parameters. As ① forward voltage; ② luminous intensity; ③ maximum operating current, etc.
(2) output parameter refers to the output side of the main parameters of the optical devices. If you use photodiode or photosensitive transistors, the parameter has ① photocurrent and dark current; ② ③ saturated pressure; the maximum working voltage; ④ response time; ⑤ photoelectric sensitivity, etc.
(3) transmission parameters
1) extreme pressure is the pressure is light-tide-for input and output between the insulation voltage values. When the light-emitting devices and optical devices in range is large, its extreme pressure value is high, on the other hand is low.
2) interelectrode capacitance optical fused together with interelectrode capacitance refers to lose big end and output capacitance between. Usually several skin method.
3) isolation impedance optical fused together with quarantine impedance is the corner-for input and output between the insulation resistance values. Its value may reach 1TG above.
4) current transfer ratio it is said that transmits light thick and strong or weak signal capability is a parameter. Whose definition is: when the output voltage to a fixed value, the output current and input diode forward current ratio.
5) response time optical coupler response time mainly refers to the delay, rise time and fall time.
Optical Coupler in working conditions to the input-side of the light-emitting diode input requirements of current pulse wave, in which case the output-side then output the appropriate pulse wave, frontier from the output pulse amplitude of 10%-90% of the time; it is the pulse rise time; from output pulse wave back along the range of 90%-10% of the time required for pulse fall time. From entering electrical pulse start point to output electrical pulse risetime of 10% of the time required for pulse delay time.