[Hallicrafters] vibrator how it works

[William L Howard]

 vibrator how it works

For anyone who wants to make a demonstration vibrator unit, I took a Radio 
Shack 12 volt relay and wired one set of contacts to act like a door buzzer 
and the other set was wired to the secondary of a Radio Shack Transformer. 
This vibrates too fast for the second contact to make contact with the NO 
position so I added a capacitor across the relay coil winding which holds it 
closed long enough to make contact with both sets of contacts. The 
transformers 115 volt primary, now being used as a secondary puts out an AC 
current much higher than the original 12 volt input. I then ran this through 
a voltage doubling circuit.

Be prepared for some very strange voltage readings!

Bill Howard