10VA 400Hz Sine Wave Generator

Some years ago we were asked if we were interested in designing a small fixed frequency sine wave generator operating from 26V DC and supplying about 10VA of power. The customer had previously approached many companies who were associated with this type of design but none were interested because of quantities required, very low power rating and low target pricing. We said yes, even though it was not our normal field, and then set about the task on an innovative basis using circuit elements that we understood well. Our understanding of voltage regulators, power protection circuits, transformers and power amplifiers all helped us to produce a simple cost effective design that has now been in service for many years and has outstanding reliability.