Craig Anderson's Home Page


Hi! You have reached the home page of Craig Anderson, one of the 4 C's. While you are visiting my web page, also check out the pages of my wife, Cathy, and my sons, Casey and Corey, as well as my patents for Sealed Inductively Powered Lamp Assembly and Light Assembly and Mounting Apparatus, and my voltage-doubler circuit.

flash 
tubes

Xenon Flashtubes

My experience in electronics has been centered around xenon strobe power supplies. These power supplies provide 2, 3, 6, 8, 16, and 24 joules of energy to be discharged through a xenon flash lamp at repetition rates of 1 to 2 hertz. Peak voltages range from 300 to 450 volts DC, with input voltages of 12 through 48 volts DC. I've participated in these switching power designs using both bipolar and FET power semiconductors. Special care has to be given to the energy storage capacitor, which is generally an aluminum-electrolytic type: deep and repetitive discharge causes gasification of the electrolyte and actual physical movement of the core. the core is generally made up of a strip of aluminum foil, which is highly etched to increase its surface area, wound with a paper separator that acts as insulation. This assembly then is impregnated with an electrolyte, generally containing a glycol compound. If the foil is too highly etched, the capacitor will overheat, causing the electrolyte to turn into a gas, which will vent either at the end seal or at some predetermined, weakened point. Transformer design has to take into account the unstable condition of repeatedly shorting the secondary with each discharge of the flashtube. Flashtubes themselves are their own science: the mean free path between anode and cathode, the blend of metals in the cathode, the fill pressure within the envelope, as well as the shape of the envelope all play a big part in this science. Generally, strobe beacons use a fresnel lens to concentrate their light in a horizontal plane. The light leaves the flashtube in a very incoherent manner. A lens that has inner vertical sine-wave shape columns coupled with external horizontal fresnels efficiently redirects the light.

fresnel
lens

Fresnel Lens


capacitor

Capacitor (end vented)


capacitor

Electrolytic Capacitor Core


Craig Anderson -- craig@the4cs.com

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