Modular hearing aid

A hearing aid comprising in combination

• (a) a circuit board having conductor strips thereon, a first side and an opposite second side and an edge zone along said first side;
• said second side including a cutout bounded by border edges;
• (b) first plug-in elements mounted on said circuit board externally of said edge zone and being electrically connected to selective conductor strips;
• (c) a plurality of circuit board-supported modular structural units;
• (d) second plug-in elements mounted on each said circuit board-supported modular structural unit;
• said first plug-in elements cooperating with respective second plug-in elements for securing selected said circuit board-supported modular structural units on said circuit board;
• (e) a battery holder mounted on said edge zone for receiving a battery for the hearing aid;
• and
• (f) a microphone unit having opposite side faces and means defining a groove on each said side face;
• said microphone unit being received in said cutout and supported by said circuit board by an interengagement between each said groove and a respective said border edge.