Crystal earphones
A crystal earphone is a high-impedance earphone that is based on the piezoelectric effect. A mechanical deformation in certain crystals such as quartz is achieved by an applied electrical voltage . With an alternating voltage , such as that of an audio signal , this creates an audible oscillation. The quality is poor, but the sensitivity is high.
Crystal earphones are therefore used for low signal strengths without any particular quality requirements. Simple medium-wave radios , such as the detector receiver, can be operated without a battery only through the signal strength of the antenna. These simple radio receivers were common from the beginning to the middle of the 20th century, but are practically no longer of any importance today. Since crystal earphones are otherwise rarely used due to their poor sound quality, they are only available from specialist electronics retailers.
literature
- Thomas Görne: Sound engineering. 1st edition, Carl Hanser Verlag, Leipzig, 2006, ISBN 3-446-40198-9
- Gustav Büscher, A. Wiegemann: Little ABC of electroacoustics. 6th edition, Franzis Verlag, Munich, 1972, ISBN 3-7723-0296-3
Individual evidence
- ^ Friedrich Benz: Introduction to radio technology. Springer-Verlag, Vienna 1937.