In an effort to elucidate the plasma generation mechanism of the semiconductor bridge (SCB), currents were forced to flow through a polysilicon bridge with a resistance of 1 Omega, while the voltage drop was measured to obtain the in situ power dissipation through the bridge. The energy stored in a 25 muF capacitor was used to activate the plasma. The typical behavior of two peaks in the voltage-time curve was observed. It is inferred from the photodiode signal that the second peak in the voltage curve results from the plasma generation of the bridge material. The breakdown voltage of the electrical discharge at high pressure proved that the SCB is an effective plasma generator. The experimental data for the no-fire condition, directly related to the safety of the explosive system, is compared with the analytical results from a theoretical model. (C) 2002 Elsevier Science B.V. All rights reserved.