Abstract: With the increasing demand for geological exploration in complicated terrain in China，the

development of helicopter transient electromagnetic system（HTEM）has been paid more and more attention. A pulse current transmitting circuit with multi-excitation sources was proposed to meet the demand of transmitting signals of HTEM system. The operation principle and circuit modes of the circuit were analyzed in detail，and the detailed circuit simulation parameters and simulation results were given. A set of principle prototype was developed，and the peak emission current of the prototype was 800 A，the maximum emission magnetic moment was more than 1.2 million A·m2，and the maximum peak current of the trapezoidal wave was 70 A. The multi-excitation source pulse transmitting circuit proposed can effectively improve the detecting ability of helicopter transient electromagnetic system to deep and shallow resources，which has a certain reference significance for the design of helicopter transient electromagnetic transmitter.

      Key words: helicopter transient electromagnetic system（HTEM）；multi-excitation source pulses；circuit simulation；power electronic