Understand the difference.

Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

OPTO-TR

Symbols

Phototransistor optocoupler

An optical isolation component using an input light emitter and a transistor output on the isolated side.

Drawing use

Schematic

Application

Electronic components

Reference family

Manufacturer

A distinction that matters

Optical isolation separates electrical domains; the current-transfer behaviour and output polarity are component-specific.

Full referenceAdd to legend

SSR

Symbols

Solid-state relay

A solid-state relay switches an output through semiconductor circuitry in response to a control input. Control isolation, output type and leakage depend on the chosen product.

Drawing use

Schematic

Application

Control circuits

Reference family

IEC / Manufacturer

A distinction that matters

An SSR has no ordinary mechanical contact gap and must not be treated as a disconnector.

Full referenceAdd to legend

Original educational previews. Follow the source references on each full entry for the appropriate standard or selected product.