Flash and bang.

My next yarn was to be about flash and bang. Here it is as planned, if somewhat late.

An x-ray generator consumes a lot of energy to produce x-rays. Generally, the generator is connected directly to the building power source that supplies the energy that makes the mysterious rays. A power station right next to the hospital is ideal.

This is a bit technical, so stay with me.
First of all, a circuit in the generator charges a bank of high capacity capacitors. Sounds obvious but the capacitors are very dangerous when charged.
Following that circuit is a control section that releases the enormous energy stored in the capacitor. This is done by a device called an inverter.
The direct current released from the capacitor is inverted to a high frequency (15kHz) alternating current at about 350V. This is fed into very large transformer, that steps up the voltage to around 80 to 120 thousand volts (or 80,000 to 120,000V). That's a lot of volts, enough to make electrons jump across a gap inside a glass vacuum tube, slamming them into a tungsten anode with such force, that energy is released in the anode as x-rays.

I was called to investigate why no x-rays were being generated. I found the inverter devices in the generator were faulty, very faulty. The inversion is the job of six monster transistors. Two transistors had failed catastrophically, blown open by the in-rush of energy, popped like corn. I replaced the transistors, after having to import them from overseas. Two were gone, but I replaced all six. It was an old generator and parts are hard to find.

Having powered on the generator again, still no action and no x-rays.
I began to investigate the inverter control circuit. I probed the components with my volt meter. Suddenly, an intense flash dazzled me. The accompanying explosion slapped me to the floor. I sat dazed, everything a weird shade of yellow and all around, strangely quiet.

The next sensory experience was a concerned staff member who had rushed to see if I was OK.
"Are you OK?"
Like an idiot, I replied "Is who OK?"
As it turned out, even though the power was turned off, the capacitors were still in a state of charge. They dumped their walloping energy across my meter probes. I'd carelessly contacted exposed cables. Probes are usually made of brass, an excellent conductor. When a lot of current suddenly rushes out, brass probes turn to vapour. Mine vapourized with a blinding incandesence causing a violent expansion of super heated air, my own clap of thunder. I thank God it wasn't me who was crisped.

I looked at the time. 5.30PM.
"Enough for one day" I thought and pledged to wait until the capacitors were quiet and resting before disturbing them again.

Next time, electronics goes camping.