The Vibrators

So, since I am a bit older than most of you, here goes. OK a lot!
Back in the 40s and 50s, the first thing you would hear when you turned on the car radio was a humming sound. You would hear it usually until the radio warmed up at which point you would hear the music or whatever. If at that point you turned the volume clear down, you could hear the vibrator again unless you were driving fast with the windows down.
Now, the whole radio didn't need to warm up, but the tubes had to warm up and that required high voltage. The car batteries back then were only 6 volt (but even if they were 12 volt, it wouldn't matter).
So ... there was a vibrator that would vibrate. The vibrating part had electrical contacts on it that would make and break contact with each vibration. From the 6 volts of direct current (DC) that the battery was supplying, this action would create pulsating direct current. That electrical current would then pass through the primary windings of a transformer which would create alternating current (AC) at a higher voltage in the secondary windings of the transformer.
Then, this higher voltage AC was used to power the tubes. The tubes did some of the main work of processing the radio signals from the antenna into audible sound. There was a filament (like in an incandescent light bulb) that would heat up and glow red inside the tubes.
Then along came semiconductors (transistors and then, integrated circuits, etc.) and the demise of the vibrators and tubes.

If you want some vibrators, here they are:


Only 9 bucks for the set. Just go to cgi.ebay.co.uk. Who knows?

More about the tubes later.
Love,
me