Schemdraw

0.22 · active · verified Tue Apr 14

Schemdraw is a Python package for producing high-quality electrical circuit schematic diagrams. It allows users to create diagrams by adding circuit elements one at a time using Python methods. It supports a wide range of components including resistors, capacitors, diodes, transistors, opamps, logic gates, and can also generate timing diagrams, state machine diagrams, and flowcharts. The current version is 0.22 and it has an active development and release cadence.

Warnings

breaking The `Drawing` class introduced a context manager (`with schemdraw.Drawing():`) in version 0.14. Using the context manager syntax with older versions will result in an `AttributeError: __enter__`.
Fix: Upgrade to schemdraw version 0.14 or newer. Alternatively, for older versions, instantiate `Drawing` directly and use `d.add()` or `d +=` followed by `d.draw()` and `d.save()` outside a `with` block.
gotcha When running schemdraw on headless servers or environments without a GUI display, calling `d.draw()` can lead to failures as it attempts to open an interactive Matplotlib window.
Fix: To prevent this, set the Matplotlib backend to a non-GUI option (e.g., `matplotlib.use('Agg')`) *before* importing schemdraw. Instead of `d.draw()`, use `d.save('filename.svg')` to save the output or `d.get_imagedata()` to retrieve image data.
breaking As of version 0.18, subclasses of `ElementCompound` must define their `Segments` within a `setup` method instead of the `__init__` method.
Fix: Refactor custom `ElementCompound` subclasses to move segment definitions from `__init__` to a `setup` method.
gotcha The `schemdraw.logic.logicparse` function returns a `Drawing` object itself and should *not* be placed inside a `with schemdraw.Drawing():` context manager. Doing so can result in blank output or unexpected behavior.
Fix: Call `logicparse` directly, e.g., `d = logicparse('expression')`, and then call `d.draw()` or `d.save()` on the returned Drawing object.

Install

pip install schemdraw Basic Installation
pip install schemdraw[matplotlib] With Matplotlib backend dependencies
pip install schemdraw[svgmath] With Ziamath for SVG math rendering

Imports

schemdraw
```
import schemdraw
```
schemdraw.elements
```
import schemdraw.elements as elm
```
SchemDraw
```
import schemdraw
```
Older versions (pre-0.7, pre-PEP8) used 'SchemDraw' with a capital 'S'. The current recommended import is lowercase 'schemdraw'.

Quickstart

This quickstart code creates a simple RC circuit diagram and saves it as an SVG file. The `with schemdraw.Drawing():` context manager is the recommended modern approach for creating and saving drawings, handling display and saving automatically upon exit.

import schemdraw
import schemdraw.elements as elm

with schemdraw.Drawing(file='basic_rc_circuit.svg') as d:
    d += elm.Resistor().right().label('1Ω')
    d += elm.Capacitor().down().label('10μF')
    d += elm.Line().left()
    d += elm.SourceSin().up().label('10V')
# The drawing is automatically saved to 'basic_rc_circuit.svg' upon exiting the 'with' block.

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