by EWBrown » Fri Jul 23, 2004 11:43 am
No, it's not an adult toy...
What it is is a cross between a buzzer and a relay. Typical operating frequency was about 115 cycles (they didn't call them Hertz back then).
There are two versions: the simple version has four pins, and one set of contacts which alternately switch the 6 or 12 VDC to the low voltage primary of the transformer (either 12 VCT or 24 VCT). The rectification was handled by an 0Z4 or 6X4. The Synchronous Vibrator has six pins,
the second set of contacts is in sync with the "primary"set, and thusly rectify the high AC voltage by switching alternately in synch with the input.
Either way, the vibrator power supplies were nasty noise generators, and required some hefty RF "Hash" filtering to eliminate the strong Buzzzzzz that would otherwise interfere with AM reception (we're not talking FM or XM radio back then). A 1946 ford would most likely have a 6volt positive ground system.
Later on, solid state vibrator replacements came out, and these helped reduce the noise factor considerably.
Later on, car radios had 12V tubes that ran a 12V plate voltage (12AD6, 12AE6, etc) and a big fat round can germanium traisistor in a simple Class A arrangement. No HV needed. And they actually sounded pretty good.
My first car was a 1955 Plymouth Savoy that I bought for $125, when I was stationed at Fort Ord, California in 1970-71 time frame. It had a 6V positive ground system, and no radio. I scoured the local junk yards, found one with a vibrator for $5, and one without the vibrator for $3. Being the basic cheapskate, I went for the $3 option, and lucked onto a local Radio Shack store, that had a big peach basket full of assorted "stuff" by the front door. In it were two of teh correct 6 pin vibrators for my particular radio, fifty cents each. Got the radio installed.and it worked. And, yes, it was a current hog. Listening to that radio (8 tubes, PP 6AQ5s, about 8-10 watts out) with the engine off resulted in a dead battery pretty darn fast. Good excuse generator when "kanoodling" with the young ladies, watching the submarine races, but it was a real PIA otherwise.
So, in a rather large and bloated nutshell, that is Vibrators 101.
/ed brown
Real Radios Glow in the Dark