1、This module is used when the actual operation requires isolation control and voltage conversion. 2、It can realize 3.3V or 5V to control the interface of 3.6--24V voltage level. After the control terminal is turned on, the controlled terminal will also be turned on. 3、Photoelectric isolation has strong anti-interference ability. Can drive big behindPower triodes, MOS tubes, etc., where high voltage driving is required, can also directly drive low power 24V relays. 4、If it is a pulse signal, please note that the limit of 817 is below 4KHZ. If the control signal is greater than 4KHZ, please do not use this module, it will not work properly. 5、Through the jumper cap can achieve whether the output is high potential output or low output.