Harshness, Clicks and Pops

Thank YOU all for very useful contributions ......

Today, it might seem I'm going off-topic.

As Dr. Jones said, "you can learn a lot from what you know." He was talking about observations.

Say if you wanted to learn about high impedance, low impedance, and transformers; firstly, you could look into the outside air to see if there are any overhead power lines.

The power in this country is alternating current at a frequency of 50Hz.

You could get an old 64-ohm live-chassis TV speaker in series with a 40-watt lightbulb (remember them!) and wire to a 13A plug, but I wouldn't recommend it. However, by doing so, I taught myself (aged 9) what 50Hz sounded like.

Going a little off-topic, it made an excellent spark transmitter. By tuning the "steam radio" between stations and chopping live or neutral wires, bareing their ends, and flicking them together, the radio responded with a hard click-clop sound. The click-clop sound became louder by winding several turns of insulated wire around an old jam jar and putting them in series with the speaker and light bulb.

As is the law, I have to tell you not to do this at home! It is incredibly dangerous, and the 240 volts 50Hz ac current gives you a right jolt of a tickle up your arm and into your chest! No, don't try this at home. You might think it somewhat remiss of mum and dad letting me do this, but they didn't know what I was up to.

If you've ever looked into a consumer unit - the box with all the fuses/circuit breakers in it - you might note that the live, neutral, and earth busbars are chunky pieces of copper.

There might be other houses on your street/lane/road? They also have consumer units containing hefty busbars.

If you laid all the busbars (let's choose the nice looking neutral ones) in a suburban street side by side, and if they magically became plasticine, you could squeeze them together (without increasing their lengths) and mould them into a large cylindrical shape - I think you'd need two hands - it would be a large diameter cylinder!

It might be that there are 100 houses surrounding an electricity "sub-station," and so we need more plasticine! The eventual cylinder's diameter is the neutral conductor's diameter required to carry the current for all those houses. You'd have the same diameter for the live conductor. Woah! That's some incredibly thick cable!

However, the overhead cable, which carries all that power, is only about 12mm in diameter (don't climb up to check!) It doesn't compute - how can that be?

Don't miss the next thrilling installment!

.....''If your transformer "preamp" has an input impedance of 100k and transforms up to give a gain of 10, its output impedance is 1meg.

I don't have much patience to continue trying to explain the bollocks expounded by these pirates, so if you didn't understand, well, you never will.'''