Resonant Tunnelling Transistor Demo

Colin Moffat
Image Processing Group
Department of Physics and Astronomy
Universty College London
Gower Street
London. WC1E 6BT

Tel. 0171-209 6582
Fax. 0171-209 6580

The program embedded within this document provides a demonstration of the 
bistable nature of a pair of resonant tunnelling transistors connected in 
series.  It enables the user to customise the following:

	1. The peak output current of both the load and driver devices
	   while they are receiving no inputs apart from the clock
	   voltage, Vclock.
	2. The voltage peak of the clock voltage (which is the same as 
	   the size of the voltage scale along the x-axis).
	3. The maximum current permitted (the size of the current scale 
	   along the y-axis).
	4. Up to 4 base contacts can be added to both the load and the
	   driver devices.

Once the current-voltage characteristics of the load and driver devices
have been specified, the clock voltage can be swept across the bistable
pair.  As Vclock rises up to its maximum value, the intersection point
of the two curves (which corresponds to the output voltage) will vary
depending on the load and driver characteristics set by the user.

This output voltage will finally settle into a value corresponding to a
high or a low digital output state. 

In order to execute this program you will must be running Netscape 3 or
above , and have the Tcl/Tk plug-in from Sun Microsystems
(both are free to non-commercial parties).

Operating instructions for the program are available here.
The embedded Tcl/Tk plug-in source code is available here.
The standalone Tcl/Tk application source code is available here.




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Last updated: 23 December 1997 by d.crawley@ucl.ac.uk