Historical information

The first all transistor hearing aids appeared in 1953. They were created to replace vacuum tubes; they were small, required less battery power and had less distortion and heat than their predecessor. The vacuum tubes were typically hot and fragile, so the transistor was the ideal replacement. The size of these transistors led to developments in miniature, carbon microphones. These microphones could be mounted on various items. There were body hearing aids where the earpiece was connected to the hearing aid and battery pack worn on the body. Ear level hearing aids consisted of eyeglass, behind the ear (BTE), in the ear (ITE), and in the canal (ITC, CIC) hearing aids.

Significance

A new aid type, the Calaid V, was introduced featuring a forward facing microphone, and three potentiometers for adjustment of maximum gain, maximum power output, and low frequency roll off. The Calaid V was introduced in the early 1980s and remained the most frequently used aid in NAL's service for the next ten years (From: THE CALAID: AUSTRALIA'S OWN HEARING AID by Laurie Upfold and Ray Piesse

Physical description

Single Behind-the-ear hearing aid. Provided and manufactured by the NAL (National Acoustic Laboratories), part of the Commonwealth Department of Health.

Inscriptions & markings

"CALAID/V" on bottom face