Friday, November 26, 2010

Magic Smoke

No, I haven't let any of the Magic Smoke out of any of my equipment lately, but I thought those of you who work on cars, particularly British cars, might find this replacement item quite handy to have around.
Replacement Lucas Smoke
Side Jokes:
Why do the English drink warm beer? Because they have Lucas refrigerators!
Who is the Lucas Electric Company named after? Lord Lucas, Prince of Darkness!
If you've ever owned a car with Lucas Electric components, you'll know exactly what I'm referring to.
Now, if you've ever worked on electrical/electronic stuff, you've probably heard the term "Smoke Test", which is the first test you run on a recently assembled or rebuilt unit. You power the unit up, carefully checking and hoping you've assembled and wired it correctly, because if you haven't, you'll let the Magic Smoke out of it, and it won't work any more.
In Amateur Radio we have a phrase "Tune For Maximum Smoke", which means to load up a transmitter to the point where any further increase in the loading control makes it impossible to find a "dip" in the plate tuning control.
Usually the plates (Anode) in the output tubes are glowing red (or orange!) before you hit this point, so you generally don't get any more output power by loading the transmitter this far, and in some cases the output power actually drops off.
These days, with solid-state equipment and broad-band output stages, you don't have to do the "load, dip, load, dip" dance when you change frequency or bands. Of course you also can't load up a wet string for an antenna (I've done it. A story for a later date) because the components are fixed value, and even if the rig has a built-in "Antenna Tuner", they don't match a very wide range of impedance, and the equipment will automatically fold-back the output power to protect itself.
And since I'm coming down with a cold, I think I'll "fold back" the covers and hit the hay!
Enjoy the rest of the weekend!

1 comment:

Keep it civil, please....

A Bit Of Rearranging In The Electronics Shop

 Since I've been cranking away on projects, I decided to rearrange things on the bench a bit to make it easier to use my test equipment....