diff --git a/src/hei_chip.hpp b/src/hei_chip.hpp
index 20b0b8c..cc8995f 100644
--- a/src/hei_chip.hpp
+++ b/src/hei_chip.hpp
@@ -13,6 +13,14 @@
 {
   public: // Constructors, destructors, assignment, etc.
     /**
+     * @brief Default contructor.
+     *
+     * In general the default constructor should not be used, but it is needed
+     * for some STL functions.
+     */
+    Chip() = default;
+
+    /**
      * @brief Constructor.
      * @param i_chip See description for iv_chip.
      * @param i_type See description for iv_type.
diff --git a/src/hei_signature.hpp b/src/hei_signature.hpp
index b820600..eb02b88 100644
--- a/src/hei_signature.hpp
+++ b/src/hei_signature.hpp
@@ -17,7 +17,12 @@
 class Signature
 {
   public: // Constructors, destructor, assignment, etc.
-    /** @brief Default constructor. */
+    /**
+     * @brief Default contructor.
+     *
+     * In general the default constructor should not be used, but it is needed
+     * for some STL functions.
+     */
     Signature() = default;
 
     /**