Ignition circuit for explosive devices and the like

Claim 1

In an ignition circuit for an explosive or the like for producing an electric spark between spaced electrodes, the combination of: a step-up transformer having a primary winding and a secondary winding on a ferrite core; means for directly connecting said secondary winding to said spaced electrodes; a transistor having a base and emitter and collector electrodes; a battery having positive and negative terminals; an on-off switch; circuit means connecting said transistor electrodes, primary winding and switch in series with said battery; an integrated circuit free running multi-vibrator having a first control voltage and reset input, a second trigger and threshold input, a circuit ground, a third discharge input, and an output, with said switch connecting said first input to one terminal of said battery and with said circuit ground connected to the other terminal of said battery; a first capacitor connected between said other terminal of said battery and said second input; first and second resistors connected in series between said first and second inputs, with said first and second resistors interconnected at said third input; and a third resistor connected between said output and said transistor base.