Physics-circuits library, made for RustFig (original work, MIT OR Apache-2.0).

Lumped circuit elements the way physics papers draw them, filling the gaps of
xfig's Electronic library: resistor (rectangle IEC and zigzag), capacitor,
inductor, Josephson junction (cross in a box, plain cross), SQUID loop, DC and
AC voltage and current sources, battery, transmission-line segment, variable
(arrow) resistor, capacitor, inductor and Josephson junction, grounds (earth
with three bars, chassis, protective earth, analog and digital ground),
transformer and mutual inductance, port, terminal, wire junction dot, and three
examples (example_rlc, example_transmon, example_resonator).

Every part is one compound, in one orientation (two-terminal parts horizontal,
grounds pointing down); turn it with xfig's Rotate modes.
All two-terminal parts have their pins exactly 1 inch apart on the 1/4-inch
grid (horizontal: (1/4 in, 3/4 in) and (1 1/4 in, 3/4 in)), so a circuit
joins with grid snapping on. Grounds have one pin, on top;
transformers four pins on the grid. Labels in the examples are LaTeX text
with the TeX flag ($C_c$, $E_J$).

The files are written by `cargo xtask libraries` (xtask/src/libraries/circuits.rs);
change the generator, not the files.
