Instrumentation Geophysics: Design and Construction of a DC Variable Power Supply

摘要

This work demonstrates the design and implementation of a 3, 6, 9, 12 and 24 Volts switching mode power supply system that replaces battery as a major source of direct current (DC) voltage for electronic equipment that can be used to energize electrodes, in geophysics field work that involves electrical resistivity surveys, seismographic and magneto-telluric surveys. The switching mode output of a variable power supply system produces direct voltages of 3, 6, 9, 12, and 24 Volts that are selected by a multi-output switch. These voltages are stepped down from a 220 Volt alternating current (AC) main terminal by an auto (variable taps) transformer and thereafter rectified and smoothened. This smoothing process by a bridge rectifier converts AC to direct current (DC) and filters off the associated impurities and ripples. The capacitor used for each stage has the rating of 2200microfarad (μf) and 35Volts.