Analogue hearing aids have a microphone that picks up sound and converts the sound into small electrical signals. These signals vary according to the pattern of the sound. The signals are then amplified (made louder) and fed to the earphone on the hearing aid so you can hear them.

Most of the better analogue hearing aids use ‘automatic gain control’ (AGC). This amplifies quiet sounds until they are loud enough to be heard, but gives less amplification to sounds that are already loud, so you’re protected against uncomfortably loud sound levels. But analogue hearing aids don’t have all the features that come with advanced digital aids, and can’t usually be set to suit your individual hearing loss very precisely.