A confession

[Hunts smoothing bomb]

Originally Posted by Buzby123

I should be able to put 240v into the 12v side, and get 4,800 volts on the other. I was hoping nearly 5kV would make a nice spark.

Connected to mains , I grabbed the output wires intending to bring them together to make a spark.

I'm very surprised that the transformer didn't instantly burn up or the fuse on the mains side did not rupture as the 12v winding would have had negligible impedance at 230/240v

Cheers

[duncanlowe]

Originally Posted by Buzby123

As a youngster, probably 13ish, I knew transformers could work both ways, and would change the voltage accordingly.

i.e 240v in / 12v out could be used as 12v in / 240v out.

As the ratio both ways is 20:1, I should be able to put 240v into the 12v side, and get 4,800 volts on the other. I was hoping nearly 5kV would make a nice spark.

This reminds me of my early days as a trainee. The other trainee in the same lab was building a power supply. Connected up, plugged in and switched on, and the mains input fuse opened. So he tried a higher rated one and that opened too. Now instead of stopping and thinking, he went for an even higher rated one, which didn't so much open, as cease to exist. He asked me to look at what he'd done, and he'd connected the secondary to the mains so likewise it would have been trying to produce a few KVs but for a very short time! Susprisingly when the wiring was corrected, it worked OK.

[Radio Wrangler]

Originally Posted by Buzby123

It blew the house fuses, and I am very, very lucky to still be here !

There were a good few confessions in that post

As a young school kid, I built a series of progressively improving oscilloscopes, all with mains derived EHT! How I'm still alive, I don't know.

David

[lightning]

At least you did something constructive, as in you actually built something.

My dad didn't live with us and one weekend he brought me one of those big bureau type radiograms
lt actually sounded really good from memory, but after he had gone l was messing around with it trying to fit new dial lamps.
l shorted something out and after that the radio part wouldn't work.

So l heaved it out of my upstairs bedroom window.

Another time, l connected up an old valve TV in the garage and took the back off, then squirted water into it with a water pistol.
Not surprisingly the raster disappeared, so l left it turned on and went out to play.

lt says a lot about the robustness of those old chassis, that when l came back later it had dried out and come back on.

[G6Tanuki]

As ten-year-old, just starting to dabble in radio, I somehow imagined that radio-waves flowing through the mysterious "aether" were like fish, and so an antenna made in the form of a net would be good to catch them.

Back then, every farm used electric-fence-wire that was an orange Nylon-cord with a couple of metal strands woven into it. I gathered a load of this, along with scrap electric-fence insulators, and wove a sort-of-net which I then hoisted up 40-feet-or-so between two conifers in the back-garden.

With this contraption - along with its downlead - which must have contributed most of the pickup - I regularly received Luxembourg on one of the cheap-and-cheerful 1-V-1 TRF radios that everyone had back then.

In retrospect, the TRF was a 'live chassis' thing [only the heaters were powered by a transformer, the HT was direct-mains-rectified using a big finned Selenium thing].

Thankfully, nobody ever touched my "SkyNet" antenna!

[Radio Wrangler]

That's quite mild compared to the theoretical backing of some proprietary aerials being flogged back in the thirties.

David

[Al (astral highway)]

At 14 I was a rogue. Using a model motor to chop up DC from a battery, and an output transformer from a transistor radio, I made a source of HT and taped the contraption to some foil to give my form tutor a jolt when he opened his desk drawer.

I also made a simulator to sound exactly like the end of lesson beeps and for a day I made hay by setting it off a few minutes before lessons were due to finish. I was a pain as far as the teachers were concerned , but acquired kudos among my peers !

[Panrock]

Apart from dropping a massive B40 naval receiver onto the paving stones below from a 3rd storey window, my speciality was blowing up 'Sparklets' soda water gas bulbs, by connecting them across the 4v secondary of an ex-Murphy A122 mains transformer. These exploded with a serious bang.

Mods, if you think my post is possibly illegal, please delete.

Steve

[Radio Wrangler]

Well, Lightning ought to be feeling more comfortable with his past knowing that many of us have histories just as bad through to a lot worse than his.

And they complain about the yoof of today!

Of course, rather a lot of people haven't confessed any terrible deeds at all, but that may just be an indication that they are better at keeping schtumm.

(I didn't mention burning out a VCM II meter then stripping it for parts, did I get away with it?)

But this thread is a bottomless pit, so let's slide the nice big cast iron lid back into place to stop anyone else falling in.

David