ELECTRONIC DELAY DETONATOR

PCT No. PCT/JP96/02066 Sec. 371 Date Jan. 23, 1998 Sec. 102(e) Date Jan. 23, 1998 PCT Filed Jul. 24, 1996 PCT Pub. No. WO97/05446 PCT Pub. Date Feb. 13, 1997An electronic delay detonator comprises an electronic timer (100) and an electric detonator (200) fired by ignition of an ignition element. The timer includes an energy charging circuit (120) for storing electrical energy supplied from a power supply, a delay circuit (30) for counting a time period by using the electrical energy stored in the energy charging circuit to thereby output a trigger signal, and a switching circuit (140) for supplying the electrical energy stored in the energy charging circuit to the ignition element in response to the trigger signal. To an impact externally applied to the electronic delay detonator, a lower limit of an impact value in an induced detonation range of the electric detonator substantially overlaps with an upper limit of an impact value in a range in which the electronic timer is operable. Thus, no explosive remains misfired even in adverse use environments. When the damage of the quartz oscillator (131) is detected, the electric detonation is fired in response to the detected signal.