Photocouplers and Optical Isolation Components
Browse photocouplers for optical signal isolation, alongside boards that use optical isolation in sensing or switching. “Photocoupler” and “optocoupler” are commonly used for the same device family, but products here are not all the same part: the selection spans discrete ICs, gate-driver devices, optically controlled switches, and assembled modules. Select by output function and the exact variant, not by the shared keyword alone.
Discrete photocoupler families
PC817 and EL817-family phototransistor output parts, 4N-series couplers, TLP, LTV, PS and HCPL models appear in through-hole DIP and surface-mount SOP/SSOP offers. Other listings include faster logic-output isolators such as 6N137 and HCPL-2601, linear couplers such as LOC110, multi-channel versions, and triac-output MOC302x, MOC304x and MOC306x options. AQY, AQH, CPC and related optical solid-state switches serve a different load-switching role from a logic optocoupler. A model suffix or package change can alter pinout, transfer ratio, output behavior or operating limits, so compare the chosen part's datasheet.
Isolated gate drivers and assembled boards
IGBT/MOSFET gate-drive photocoupler choices include TLP250H, TLP350/TLP351/TLP352, HCPL-3120 and FOD3120/FOD3150 variants. The TLP250H DIP-8 offer provides separately selectable 5-, 10- and 20-piece quantities; its seller-stated isolation, common-mode immunity and certifications must not be generalized to other models or treated as independently verified. Also present are relay modules with optocoupled inputs, MOSFET switch boards, PLC/RS485 digital I/O assemblies, AC-detection boards and slotted optical speed-sensor modules. An opto-isolated module is an assembled board, not a pack of bare ICs, and a magnetic isolator listing is a separate technology.
How to choose the right option
- For IC replacement: match complete part code, suffix, outline and pinout; compare LED drive, current-transfer ratio or logic threshold, output topology, supply limits, propagation delay, isolation specification and operating temperature.
- For gate drive: check output supply and current capability, timing, common-mode behavior and the power device's gate-charge needs. A standard PC817-type phototransistor is not automatically a gate driver.
- For a module: verify input supply and trigger polarity, channel count, contact versus transistor output, allowable load type, isolation layout and board revision. Do not assume a board is safe for mains merely because it contains a photocoupler.
- For quantity: a heading with multiple model codes usually describes a menu, not a mixed shipment. “Color” and “Model Number” may actually specify model, voltage, pack size or a distinctly labelled assortment kit. Check the selected variant and reconcile conflicting seller quantity or condition claims before ordering.
Frequently asked questions
Are photocouplers and optocouplers different?
The terms often name the same optical-isolation family. The precise device function still depends on its selected part number and output design.
Can a TLP250H DIP-8 offer replace a TLP250 or TLP350?
Not based on a similar name. Compare the original design, package, pinout and manufacturer specifications for each full code.
Does a relay module provide complete safety isolation?
Not automatically. Verify its power domains, board clearances, load limits and documented installation requirements; use qualified procedures for mains and high-energy circuits.
Is every multi-model listing an assortment?
No. Choose a specifically marked kit only when you want a mixed set; otherwise the selected variant may supply one model in the stated quantity.
