12V car cig lighter adapters - safe?

you can alos get a lightining strike on a power line, and destroy your house wiring.

I have never had electronics connected to a car alternator blow up.

I have had my house wiring destroyed - and a lot of kit with it - by a direct strike on the overhead PHONE wire.

Almoast all electronics in the car..more these days than ever before, will have capacitors and clamps to absorb the surges.

I did have a car with a loose battery connection...it ran Ok once it was running but died at teh traffic lights on New years day at 2 a.m. In central london. With its lights on.

So teh car had been running with no battery connected.

Nothing blew up. I simply whacked the terminal back on the battery and drive off.

This seems to be tone of these 'well yes, once upon a time one alternator with one type of controller did cause a bit of a problem' but these days its all pretty well sorted.

Stating the bleeding obvious again. And my experience counts for a lot. What is yours by the way? Mid degree course by any chance and not living in the real world yet? Nothing can be perfect down to the nth degree and if you understand anything about electronics you will know its always a compromise getting the design to work well. I'd like to test you in practice sitting at a work bench with a soldering iron at the ready and see who could come up with the first working design of say a 10dB audio preamp, a 30MHz oscillator and phase locked loop logic and lets say a 5 watt audio amp. I bet you couldn't even draw a common emitter preamp off the top of your head without looking for the info or grabbing an op amp. Prove me wrong. Tell my roughly how to go about designing the phase locked loop logic. Its very easy. Just the basics. Go on...

Graham

I wouldn't bet on it. ;-)

For you possibly.

I already explained that

You're joking.

Of course. My point was that one can't rely on cheap Chinese manufacturers to have done this work.

I was designing this kind of equipment and digital PLLs, mixed logic families, low power requirement and RF immunity from the 1970s onwards.

I now do more lucrative things.

You're right. He shouldn't.

Then you won't find this question very taxing then. What's the reactance of a 470uF capacitor at 50Hz?

I'll let you use your calculator to work that out using (2 x pi x f x C)^-1

I haven't needed to deal in elementary exam questions for very many years.

Completely imaginary. do keep up there at the back ;-)

Tee hee. A class answer that, except that it's wrong :~). The reactance, a certain number of ohms, is a real value. It's the reactive component of the impedance that's purely imaginary. IOW in Z = R + jX the value of X is real.

Just give the answer you dreamers

Graham

But as we're talking about cars and trucks, bringing in a tank is a bit pointless.

Considering the amount of times it's been done, if it were to be possible, surely it would have by now?

Ah, but you see, we aren't scratching around in the dirt any longer and have moved on to greater things.

By 1980 I had figured out that sitting around designing electronics, although interesting and fun, was not going to offer the advancement and reward that I was looking for.

It was only to make the point that a large vehicle with electric motors is apt to generate very large spikes. I did also test and measure the electrical environment in smaller vehicles and they are far from electrically clean both in terms of conducted and radiated emissions.

My point was that if one buys properly designed equipment such as charging leads, filters etc. then yes. If it's an unknown piece of junk from China, it may not be trustworthy.

As Dave Plowman and myself predicted, You Failed This Test and proved you are just flapping your gums with bull if you cannot answer that simple electronics question. The air of BS was strongly in the air, but just had to be sure. God I couldn't have made it any simpler. Anything less and we would have been at 1st year and ohms law!

Graham

But virtually everything electronic we have comes from there. Hell, even the power brick for my Compaq is made in China.

Don't be silly. You have missed the point entirely. Whoosh.....

I don't suppose that your abilities would have permitted it.

I imagined that that was your approximate range.

Of course. That's why I used the term *unknown* junk.

If one buys a laptop and an adaptor from a reputable manufacturer then while it may have been manufactured in China, or possibly even designed there, one can have a come back to the manufacturer if something goes wrong.

If I buy a Hoo Flung Dung super special adaptor of questionable parentage but low price, I would not expect that level of support.

Moreover, if I have relatively expensive equipment, I am not going to risk wrecking it by the use of inadequately designed accessories.

Err, no. Read what I wrote again more carefully. And stop trying to make silly points.

For some reason this thread has brought out the stupid in people. Maybe its the recent weather. The subject is a known deal and has been for decades. All car manufacturers specify all electronic kit aboard cars to meet the spike levels that may be encountered, both +ve and - ve. Anyone that wants to find more about it can ask in sci.electronics.basics where real engineers are often happy to explain.

I've said it before and will say it again: if you ask about electronics in uk.d-i-y the noise will swamp the signal.

NT