# ANSI/IEEE photodiode symbol

Canonical URL: https://eloragrid.ai/symbols/ansi-photodiode
Publisher: Elora Grid
Updated: 2026-10-14
Lookup label: PD
Drawing use: Schematic
Reference families: IEEE / ANSI, Manufacturer

## Symbol convention

Convention: IEEE / ANSI
Form: Autodesk IEEE-oriented Semiconductor Components functional form
Autodesk explicitly publishes this block under IEEE Symbol Preview. The counterpart is the matching functional concept; no equivalence of every detailed standard graphic is asserted.
Related representation: [Photodiode](https://eloragrid.ai/symbols/photodiode)

IEEE-oriented graphical reference for photodiode, with public vendor evidence and drawing-reading notes.

## What it represents

The photosensitive diode form associates an optical influence with a semiconductor sensing path. The optical marker is separate from electrical bias and measurement connections, which must be read from the actual sensing circuit.
This is a convention-specific lookup based on the publisher's IEEE-labelled preview. The geometry here is independently drawn to explain the connection or operation; it is not a certified reproduction of the standard graphic.

## How to read it

- Identify the measurement circuit and any bias supply.
- Read the selected library and the project legend together. A vendor block identifier is meaningful within its named library and is not a universal standard-symbol code.

## Information to show or reference

- Preserve diode polarity
- Reference optical input
- Show sensing/bias circuit

## Important distinction

A photodiode receives light-related input, whereas an LED is a light-emitting component.

## Facts

- Convention evidence: Autodesk IEEE Symbol Preview — Semiconductor Components
- Public vendor block name: HDI1B4 (Autodesk identifier; not an IEEE symbol number)
- Standards context: IEEE/ANSI 315-1975 covers diagram graphics. IEEE lists this edition as Inactive-Reserved.
- Artwork scope: Original functional illustration; exact standard glyph and compliance are not certified

## Public references

- [Autodesk IEEE Symbol Preview — Semiconductor Components](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-EC01CFC2-47B9-4AE3-AE5E-0FB86D327A82.htm) — Autodesk. Exact public IEEE-oriented category page verifying the component name and vendor block identifier.
- [IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams](https://standards.ieee.org/ieee/315/515/) — IEEE Standards Association. Graphic-symbol standards context and official status; not a source of reproduced artwork.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.