The basic function of a Photo Coupler is that it ensures total electronic isolation, including potential isolation (as in the case of transformer) in an electrical circuit. Devices of the Photo Coupler family include Photo Transistor, Photo Darlington Transistor High speed Photo coupler and OPIC. These devices have the characteristics of excellent isolation, high CTR, compact package, high-speed operation, low decay and unit control function not being influenced by field effects. They are most suitable to be used for microelectronics, data processing and telecommunication system. Due to their high safety features, they are particularly suitable for use in switching mode power supply units.

In general, Photo Triac is used in power control of two-way triac rectifier. It is applied in circuit as level voltage ideal insulator that separate high & low voltage. It is applied in home appliance and Solid State Relay for controlling isolation voltage. COSMO Photo Triac KMOC series are available for DIP, SMD type. KTLP series are available for SOP type. The characteristics are available for 2 major functions, one is with Zero Crossing, another is without function of Zero Crossing function. Voltage are available for 400V , 600V and 800V…etc.

Photo Link is an optical transmission device that is to convert electrical signal to digital signal. The device is widely used in DVD Player, Set Top Box, PC/Notebook and Car Stereo that required professional digital audio applications.

The circuit consists of 4 photo detectors, 2 current comparators and 2 latches. The 4 photo detectors are spaced in fixed distance such that they can be controlled to a light period or dark period. The photo detectors transfer light into current, then the current comparators generate the results to the latches. If the comparator output is “l(fā)arger than”, the latch output is in set state. Otherwise the latch output is in reset state.

The KW Series photointerrupter consists of a high radiant power GaAs infrared LED and a Si phototransistor. Housed in a short lead package, this device is ideal for automatic mounting.