Saturday, July 12, 2008

There IS a reason for warnings on disposable cameras!

So, the other day at job-lot I decided to buy a disposable camera. Not to use it, but to take apart the flash assembly. I take a few spots just to test the flash. nothing special, just a $2.50 special. I know that the assembly uses several hundred volts to run the flash tube and several thousand to trigger it, but at almost no current. Therefore, it should be safe.
I take the cover off in flagrant disregard of the safety warning and chuck the film. I take off a coupla screws and pull the circuit board out. absolutely b-e-a-utiful. then, my finger bridges two solder points on the board. there's a small flash as the flas tube trips, and my arm jerks back on its own. No pain, no danger, just stupidity.
a mostly nontechnical explanation of how a flash works: A 1.5V battery powers the entire assembly. two transistors make the DC into AC - like an outlet, but 1/80th of the voltage. This 1.5VAC is fed into a transformer that converts the 1.5VAC into 300VAC (at very low, non-dangerous currents). A diode converts it to 300VDC, which charges a
capacitor. however, 300 volts will not trip the flash tube, so a trigger coil is used to generate about 4000V, which trips the tube, allowing the charged capacitor to run it for about 1/10 second.

2 comments:

mandachan said...

whatever. you should've been smart enough to know that by now.

yaaay i got an alex gordon baseball card at last night's defender's game booo he had an 0-fer (i checked. but he did have a nice diving stop and still made the throw to first)

mandachan said...

psst! hi!