Optocoupler is an electrical and photoelectric converter composed of LED and photosensitive transistors.The main principle of the optical coupler is to realize the transmission and conversion of electric and electrical optoelectronic with light as the medium.
In the optical coupling circuit,in order to cut off the transmission way of interference,the circuit of the input and output circuits must be independent and not common.As the optocoupler is a device with light as the medium to transmit signals,the electrical insulation of the output and the transmission end is realized (the insulation resistance is more than 1000000000 ohms),and the pressure is more than 1kV.The characteristics of the optocoupler can be recorded as electrical isolation and signal transmission.Optical coupler is one way transmission,no internal feedback,strong anti-interference ability,especially anti electromagnetic interference ability.It is a new type of device widely used in micro-computer detection and control system photoelectric isolation.It is widely used in PLC.
The detection of the optical coupler can be carried out in the following steps.
measurement of the transmission part of the optical coupler
The multimeter is placed in the "RX1k" block to measure the two input terminals of the optical coupler.The optical coupler between the two inputs is actually an LED,so as long as the positive and negative resistance of the LED is measured,you can judge the quality of the input.
Measuring the output part of the optocoupler
Under the premise of the transmission end,the positive and reverse resistances of the two output ends of the optical coupler are measured with a multimeter.At this time the meter's needle should indicate infinity.
The transmission characteristics of the optical coupler are detected.
The simplest method of measurement is using a double meter method.The resistances of the input and output terminals of the optical coupler are measured simultaneously with two multimeters.When measuring the input resistance indication reading of the optical coupler is relatively small,the resistance reading indication of the output terminal of the optical coupler is also relatively small.This means that the output terminal receives the optical signal and amplifies the signal.
Detection of insulation resistance of Optocoupler
The multimeter is placed in the "RX10k" gear, and the resistance between any input port and any output terminal of the optical coupler should be infinite.The explanation of the optocoupler.The edge performance is better.