An optocoupler can be used with both DC and AC signals with optocouplers utilizing a SCR (thyristor) or triac as the photo-detecting device are primarily designed for AC power-control applications with zero-crossing detection of the sinusoidal waveform. However, when an AC (alternating current) is input to the LED, the photocoupler not only outputs every half cycle, but the LED is also in danger of receiving. Optocouplers (also called Photocouplers, Optoisolators, and Optical Isolators) are available at Mouser Electronics from industry leading manufacturers. Mouser is an authorized distributor for many optocoupler manufacturers including Broadcom, onsemi, Renesas, Toshiba, Vishay & more. Optocouplers. Optocouplers, also known as opto-isolators, uses infrared light to transfer electrical signals between two electrically isolated circuits and are commonly classified by their photosensitive output device What is an Optocoupler? An optocoupler (also called an opto-isolator, photo-coupler, or optical. The optocouplers I have evaluated are PC814, H11AA1 and SFH620A-3, out of which I found SFH620A-3 to be more efficient (must be due to the better CTR). I had connected a series resistance of 440K (1/4W) and everything seems to be fine i. Unlike transformers or capacitors, which can only transfer AC signals across the isolation barrier, optocouplers can.