Heathkit EC-1

Ethan wrote: I wrote: Oops, I need to correct this. Resistive sheets belong to a category of analog computing called passive element computers in which network analyzers are probably the biggest and most well known examples. But it also includes * conductive sheets * electrolytic tanks - create 3 dimensional simulations * resistor networks * pin and rod systems * resistor and capacitor network Passive element computers normally models a physical system using only passive R-L-C components, and solve equations in which dimensions in space are the independent variables, rather than time. Applications for passive element computers include things like the simulation of * reception patterns of a receiving antenna * temperture, and pressure flow in a nozzle * diffusion of material at a transistor junction Here is an example: You solder together a large two dimensional matrix of resistors (all the same value). At each node where the resistors are soldered together you solder a capacitor connected to ground. You then apply a voltage to one corner of this resistor and capacitor network. As the current flows through the network it begins to charge the capacitors. You now have a computer that simulates the heat flow across a metal plate the size of your matrix, both over distance and over time. Without the capacitors you are simulating only over distance. A resistive sheet is a resistor matrix with a very fine mesh. The finer the mesh, the better the simulation. "Rubber-sheet computers have been used extensively to study the trajectories of electrons and gas ions in vacuum and gas tubes" -Doug ========================================= Doug Coward @ home in Poulsbo, WA Analog Computer Online Museum and History Center http://dcoward.best.vwh.net/analog =========================================