The Design And Implementation Of Transient Electromagnetic Geologic Detecting Instrumentation

Transient electromagnetic method is a new geophysical method. Its early application is in geological exploration and environmental monitoring. With the development of technology, it is used in municipal engineering, nondestructive testing, mineral exploration and so on. This thesis is based on transient electromagnetic method, starts from the characteristics of transient electromagnetic signal and analyses its working principle and process.This thesis presents a method based on the geological transient electromagnetic detector transmitter circuit, starting from the theoretical analysis for the overall topology design, and ultimately formed a complete circuit. The transmitter can use battery power source, emits bipolar current. Its output capability is strong and the turn-off time is very short. The system circuit is relatively simple with high reliability and low-cost. The machine is easy to be carried, suitable for the small-power and medium-power transmitter geological detector device.This design of geological detector transmitter circuit consists of four main components MOSFET full-bridge configuration, routing two MOSFET cut off and carried off when the logic control. All MOSFET drive signal is given by the microcontroller through the drive circuit, the control circuit on and off full-bridge circuit, and can be selected according to the different geological conditions transmit frequency. Load current in the coil size and off-time feedback to the microcontroller after sampling process, and then the corresponding parameter to be displayed in real time. Meanwhile, the over-current protection is designed to protect the system.After the actual test, I design a geological detector transmitter circuit design to satisfy the basic requirements. And for the inadequacies of the analysis carried out, pointing out possible improvement in the future. When finishing the design of transmitter circuit, this thesis discussed the characteristics of transient electromagnetic receiving signals and analyzed the receiving system’s function. By analysis and calculation, a design scheme is recommended.