Message-Id: <199905070136.SAA18809@isaac.exploratorium.edu>
To: Pinhole Listserv <pinhole@exploratorium.edu>
From: pauld@exploratorium.edu
Subject: Re: pinhole generators
Date: Thu, 6 May 99 18:36:13 +0000
Hello Yibi Smith
The generator (actually alternator but it still works
OK) will generate 12 volts or so. Say that when the
battery is depleted its voltage is at 10 volts. The
generator will bring the battery to 12 volts. When
the battery reaches 12 volts the flow of current into
the battery stops.
Here's a fluid flow analogy.
You have a pump (the generator) that will only
pump water to a height of 12 feet, no higher.
You have a bucket, the bucket is 15 feet high but
has only 10 feet of water in it. (The pump feeds
water up a hose inside the bucket.)
You turn on the pump the water flows into the
bucket filling it up. But when the water level in the
bucket reaches 12 feet the pump can't pump any
higher so it stops. So when the water reaches 12
feet the flow into the bucket stops. This is because
the back pressure from the 12 feet of water stops
the flow through the pump.
Paul Doherty
--------------------------------------------------
This message was sent using Exploratorium web mail
http://www.exploratorium.edu/