Optocouplers, Isolator ICs and Opto-Isolated Modules
Explore optocouplers and opto-isolated electronics for signal transfer, switching and sensing. This collection includes individual optocoupler ICs as well as complete relay, MOSFET, input-isolation and sensor modules. They serve different functions: an isolated relay board is not a bag of bare optocoupler chips, and a gate-drive optocoupler is not interchangeable with a general-purpose phototransistor coupler.
Choose the component type
- Phototransistor and logic-output couplers: listings include PC817/EL817-family devices, 4N25–4N38 choices, 6N137, TLP and HCPL models in DIP and surface-mount outlines. Compare channel count, input LED requirements, output type, speed, package and exact suffix.
- Gate-drive and high-speed isolators: selected TLP250/TLP350/TLP351, HCPL-3120, FOD3120/FOD3150 and related options target different drive or fast-signal roles. Check the individual datasheet's output supply, drive capability, isolation and switching timing against the circuit.
- Phototriac and solid-state switching parts: MOC302x/MOC304x/MOC306x options, AQY/AQH/CPC and other optically controlled switches differ in output topology and trigger behavior. A zero-cross part, random-phase part and DC-output PhotoMOS-type device are not equivalent.
- Ready-made boards: PC817/TLP281 input modules, multi-channel relay boards, opto-isolated MOSFET controllers, RS485/PLC I/O modules, AC sensing boards and slotted optical speed sensors are assembled products with their own supply, channel, input and output specifications. Some listings also describe magnetic isolators as alternatives to optocouplers; confirm the actual technology before ordering.
Read the selected variant, not just the heading
A title may list many part numbers without promising a mixed kit. Options labelled “Color” or “Model Number” may choose a specific IC, package, input voltage, output type, channel count or lot quantity. Some offers are single-model 5-, 10-, 20-, 50- or larger-piece packs; at least one listing offers either a named 10-piece selection or a 13-value kit. Confirm whether the selected option is a specific code or a mixed assortment, and resolve any contradictory seller quantities or condition labels on the product page. Seller claims about authenticity, certification, isolation voltage and electrical ratings are not a blanket guarantee across this collection.
Selection and safety checklist
Compare the full model number and suffix, pinout and package (DIP versus SOP/SSOP), input current and threshold, output circuit and voltage, propagation delay, channel count, isolation rating and clearance requirements. For modules, additionally verify board supply, input logic, active-high or active-low trigger, load type, contacts versus transistor output, and exact board revision. A board advertised with an optocoupler does not necessarily provide system-level safety isolation: review its layout, power domains and manufacturer documentation. AC mains detection and high-power switching products require qualified design and appropriate enclosure and protection; this collection is not a wiring guide.
Frequently asked questions
Are PC817 and EL817 automatically interchangeable?
No. Compare the exact suffix and datasheets for transfer ratio, pinout, package and operating conditions before substituting.
Does a multi-part-number title include every chip listed?
Usually the model selector identifies the chosen code, while a specifically named kit option may contain an assortment. Check that variant's stated contents and quantity.
Is an optocoupler relay module the same as a solid-state relay IC?
No. An assembled relay board can include a mechanical relay and optocoupler input, whereas a solid-state switching IC uses a different output device and has different load limits.
Can I use any optocoupler for an IGBT gate driver?
No. Select a gate-drive-rated device only after checking its output stage, supply, isolation, timing and the transistor's gate requirements.
