Transformer kickback

the second effect (when you short the input terminals together, it's not the battery terminals shorting together, it's the transformer winding shorting that's causing it) is because you are collapsing the magnetic field, and in the process dumping a huge amount of current through the primary (the primary leads being shorted together) this induces a large current in the secondary, and a very large voltage across it as a result, however, this can't be good for the battery, since it's driving a short circuit for a moment. it also may not be very good for the secondary winding, since the voltage you're producing may be enough to break down the enamel insulation on the wire and cause a shorted turn.

12V@150mA=1.8W not even enough for a 5W light bulb.
max current you can draw from the secondary is 8mA.

to get any useful power out of this you want a 12V@10A transformer (i.e. in the 100-150W class). in the above schematic, that's the type of transformer shown.

mneary said:

First, how are you expecting 8A in a 150mA transformer?

illconductor said:

hmm thanks guys.

i havent measureed the current from the secondary but im pretty sure its bugger all..

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I look up 'bugger', and it has nothing to do with electronics. Perhaps your transformer has been abused?

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I am fairly sure illconductor is English. In English, but not in American, "bugger all" means none or very little.

Bloody colonialists!

The last line of Eric Idle's Galaxy song **broken link removed** is an example.

actually, the american term would be "boogered up" which alludes to being covered with dried snot...

Boogered up (American) means broken or damaged. "Bugger all" (British) according to Diver means small or no quantity. Not even close to the same thing.

Last time I used creative language, a troll gave me negative Reputaion. Guess I have more of that to look forward to. *sigh*