On 3/18/2015 10:05 AM, Ralph Mowery wrote:
"Stormin Mormon" wrote in message
news

I could not find a web page that described the old
type vibrators (not the kind that give women momentary
high blood pressure and screaming and moaning). But
what I remember is they caused a rapid interruption in
the DC, by open and close a switch / contacts. As such
they put out pulasting DC, which ended up being
pulsating DC on the other side of the transformer.


On the output side of the transformere it was AC. That is why a rectifier
tube or diode was used. The 0Z4 was a common tube used in the old car
radios. There were some syncronous vibrators that had a set of points on
the secondary and another on the primary. This eliminated the need for the
rectifier and only the capacitors were needed to smooth out the pulsing DC.


(reply from a friend of mine)
it's the same as the spark plug circuit on the ignition.

It's not AC, it's pulsed DC.

http://hyperphysics.phy-astr.gsu.edu.../ignition.html