nilclass/circmark

WIP markup language for (a subset of) electronic circuits

circmark

A concise markup language to describe (parts of) linear electronic circuits, in order to draw them.

Examples

The following circuit consists of two resistors in parallel (R1 and R2) followed by a resistor in series (R3).

(R1||R2+R3)

This input can be rendered with cm-to-svg...

cargo run --bin cm-to-svg -- '(R1||R2+R3)'

... to produce this:

Status

WIP

Reference

The grammar looks roughly like this:

document       : twoport
               | subcircuit
twoport        : (shunt-link | series-link)+
shunt-link     : '|' subcircuit
series-link    : '-' subcircuit
subcircuit     : element
               | '(' series-group ')'
series-group   : parallel-group '+' parallel-group
               | parallel-group
parallel-group : subcircuit '||' subcircuit
               | subcircuit
element        : 'O'
               | /[RCLVIZ]/ id
id             : /[0-9a-zA-Z]+/

Elements

An Element consists of a single component:

• resistor, e.g. R1
• capacitor, e.g. C1
• inductor, e.g. L1
• voltage source: e.g. V1
• current source: e.g. I1
• generic impedance: e.g. Z1
• open circuit: O

Except for the open circuit (O) all elements consist of a letter (R, C, L, V, I, Z) followed by an identifier. The identifier can be any alphanumeric string with no spaces.

Examples

All of these are valid: R1, C27, Zth1, Lseries

And all of these are invalid: R*, C++, Z th 1

Groups

Groups represent a series or parallel arrangement of other groups. A group can also consist of just a single element (R1)

Series arrangements are denoted with the + operator, parallel arrangements with ||. || takes precedence over +, so (R1+R2||R3) means: R1 is followed by a parallel combination of R2 and R3. It does not mean R1 together with R2 are in parallel with R3.

Currently groups must be enclosed in parentheses. This may change in the future. Nested groups do not need parentheses, unless they are needed for precedence. For example (R1+R2||R3) and (R1+(R2||R3)) are the same circuit, while (R4+R5||R6) and ((R4+R5)||R6) are not.

Examples

• Series arrangement of R1 and R2: (R1+R2)
• Parallel arrangement of C1 and L1: (C1||L1)
• Equivalent circuit of a quartz crystal: (Cp||(Rs+Ls+Cs))

Twoport link

There are two types of twoport links:

• shunt links which connect the signal path with the common path, denoted by |
• series links which are within the signal path, denoted by -

A twoport link is simply one of those operators (| or -) followed by either an Element or a Group.

Twoport network

A twoport network consists of one or more twoport links.

Examples

• A series resistor surrounded by open ports: |O-R1|O
• A voltage source, shunted by a capacitor, with an open in between: |V1-O|C1

How to contribute

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