Mercury Arc Valves

How did people get DC power from AC before semi-conductors? I’d honestly never thought about it before until Kevin sent me this:

http://forums.atomicmpc.com.au/index.php?showtopic=14715&st=0

There were a few options, motor-generators being one, but efficient options were limited. These valves act like a physical diode, that uses a pool of mercury (!?!) Look at this thing, its friggin crazy:

Paraphrased from Wikipedia: http://en.wikipedia.org/wiki/Mercury_arc_valve – Current enters the pool of mercury, which boils off. Thus the large evacuated glass tube containing mercury vapor, which condenses the mercury back into the pool. When an arc forms,  mercury emits electron freely form the surface of the pool. Ionization of the vapor occurs along the path towards the carbon anode.  The carbon anodes do not emit very many electrons, thus rectifying the power.

I’ve never heard of this before, even though this was apparently very commonly used technology prior to the 1960s. To me, it looks like a hollywood movie alien technology prop:)

This entry was posted in Day to Day. Bookmark the permalink.

One Response to Mercury Arc Valves

  1. NetRon says:

    JESUS !

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s