From: jones@pyrite.cs.uiowa.edu (Douglas W. Jones,201H MLH,3193350740,3193382879)
Newsgroups: sci.engr.mech
Subject: Re: Water Transistor?
Date: 28 Jul 92 14:17:34 GMT

From article <a4lm+9d.sspatter@netcom.com>,
by sspatter@netcom.com (Samuel Scott Patterson):
> 
>                        ... Instead of electricity, it would use
> running water.  I've figured out how to do most of the
> things needed, capacitators, resistors, trnasformers, diodes, etc,
> but I don't have a clear idea of how to simulate transistors.

I've done it.  (Also note, ice is a protonic semiconductor, I've made an
ice diode, but that's not a hydraulic solution to the problem you've
stated.)

Here's a diagram of a hydraulic inverter in its two states:

                    High Pressure            High Pressure
                        Supply                   Supply
                         | |                      | |
                         \ /                      \ /
            Control ---\  |          Control ---\__|
             Input  ---/  |           Input  ---/   \
                         / \                      / \
                         | |                      | |
                      Controlled               Controlled
                        Output                   Output

There are three nozzles, I used pyres tube, drawn to between 0.5mm and 1mm
inside diameter and then broken in two to make matched pairs of nozzles.
The high pressure supply nozzle and controlled output nozzles should be a
matched pair with an inside diameter on the large size of the above range.
The control nozzle can be on the small size of the range, but having all
nozzles of equal size will work, although it limits fanout.

I used a head of less than one meter for the high pressure supply.  The
flow from the nozzles should be a clean jet, with no cavitation or spray.
The output nozzle must intercept this jet cleanly -- exact alignment is
tricky and is best done with water flowing.  I used ring stand hardware to
hold my parts, but it would probably be better to use something like epoxy
putty, aligning things when it's still soft, then letting it set.

In the left diagram above, the control input is off -- it contains no
water or the water in the tube is under no pressure.  As a result, the
water jet from the high pressure nozzle flows into the controlled output,
maintaining the output at moderate pressure.

In the right diagram above, the control input is at moderate pressure, so
that a small jet comes out.  This hits the jet from the high pressure
supply and diverts it from the controlled output, so that has no pressure
and any downstream control nozzles will not squirt.

The following diagram shows a 2 input nor gate.  I've built a flipflop
from these:

                    High Pressure
                        Supply
                         | |
                         \ /
                    ---\  |
          Control   ---/  |
           Inputs   ---\  |
                    ---/  |
                         / \
                         | |
                      Controlled
                        Output

I got the idea from an Amature Scientist column in Scientific American back
in the 1960's.
					Doug Jones
					jones@cs.uiowa.edu