Telluric currents have been monitored by geophysicists of the MTA Széchenyi István Geophysical Observatory for fifty years. In the first years the measured values were registered manually, later with analog devices and a decade ago the system was digitized. In 2013 the student group of BME-HVT improved the data acquisition and they installed a four-channel, extended frequency range, 24-bit data register device in the observatory. Uninterrupted operation of the measurement is an important requirement of the system, but it has not been implemeted yet. The aim of this thesis was to develop an uninterruptible power supply (UPS) which can be used in the observatory and in future projects, too.
This paper briefly describes the concept of telluric currents and the need for monitoring them, which is followed by the presentation of the telluric current measurement system and the specification of the UPS. The different system design alternatives for an uninterruptible power supply are analyzed in details and the optimal architecture is selected based on the provided comparison. After presenting the block diagram of the power supply, the paper provides the technical details of the circuit design. The thesis contains all the practical steps and considerations needed to build a model of the UPS. It confirms the correctness of the design by measurements performed on the completed model. The paper closes with the experiences gained through the design process and the possibilities for further improvement.