| Description |
We routinely use electrical sparks to initiate chemical reactions in combustible powders and reactive gases. The delivery can be done directly through the medium (i.e. the electrodes are embedded in the medium and a spark is created) or through an "explosive bridge wire" (EBW) configuration. In the latter, a thin metallic filament is tied between the electrodes and that material is vapourized by the electrical discharge.
The range of energy stored (how much is delivered through the spark is a good question) is on the order of 1mJ to 1kJ. Currently, all our ignition circuits are homemade and difficult to control. They are also uncalibrated and we have no measure of the delay between a trigger signal and the spark as well as the jitter in this delay. For low energy systems 1-100mJ, our designs are based on automotive ignition systems. For high energy systems, 1J-1kJ, we use a spark-gap controlled, high energy capacitor discharge. These capacitors are typically charged between 1kV and 15kV.
I need a controllable, electrical ignition systems. I'm expecting that the range of energy will not be coverable by a single device, so it is fine if, say, 3 devices are made for the ranges 1-100mJ, 1J-100J and 0.1-1kJ. The ignition system must be:
1) CONTROLLABLE: either the charging state (voltage, energy, etc) or the delivery energy is selectable by a user. The charging and discharging of the device must be controllable both manually AND by 5V digital inputs from other equipment.
2) CALIBRATED: the following quantities must be measured: the amount of energy delivered at different settings, the duration of energy delivery, the delay between triggering of the device and energy delivery, the jitter in the delay.
3) SAFE: all equipment must be possible to safely used in a laboratory setting where no EE students are present. The equipment must be shielded and produce minimal interference to nearby equipment. Safety features must be present to be able to safely discharge the system (either manually or through remote, digital inputs) if a test is aborted.
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