Outboard Transformers for Audiovisual Equipment

About four years ago, the author proposed that 24 V should be the standard voltage for operating audiovisual equipment. Several benefits of such standardization were considered: increased user safety, international compatibility, more portable equipment, more efficient optical systems, possibly lower cost equipment, and use of equipment in places that lack electrical mains. Now, it is pointed out that many of the good new audiovisual systems do employ built-in transformers to reduce the mains voltage to an optimum level for projection lamps and solid-state electronic components. The disadvantages of inboard transformers, however, are that they add substantially to equipment weight, often constitute a source of hum in audio circuits, and still require that a potentially dangerous higher voltage be supplied to the machine. It is noted that a number of electrical products for the consumer are equipped with outboard transformers — sometimes as options; tape recorders and pocket calculators are examples. It is recommended that the next generation of audiovisual equipment should also employ outboard transformers to provide the benefits envisioned earlier. Questions involving connector standardization, current rectification, grounding, centertapping, etc., are examined.

Print ISSN

0036-1682

Published

1977-07

Content type

Information

DOI

10.5594/J17478