diff --git a/contents/drawings/197.tex b/contents/drawings/197.tex
index 1f7f92a..a898a81 100644
--- a/contents/drawings/197.tex
+++ b/contents/drawings/197.tex
@@ -13,7 +13,7 @@
     %
     \draw(a1 |- T-L1.south west) node[]{\qty{230}{\volt}};
     \draw(a2 |- T-L1.south east) coordinate(start);
-    \def\x{0.05}
+    \def\x{0.05cm}
     \draw (start) sin ++(+\x, \x)
                   cos ++(+\x,-\x);
     \draw (start) sin ++(-\x,-\x)