A low input power transistorized circuit is used to generate a staircase waveform of high step uniformity. Other characteristics are low step droop, fast transition time, and no feedback

Breen, G. D.

English

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6-rn 721 
July 1964	 Brief 64-10007 
NASA TECH BRIEF 
This NASA Tech Brief is issued by the Technology Utilization Division to acquaint 
industry with the technical content of an innovation derived from the space program. 
Low-Power Transistorized Circuit Provides Staircase Waveform 
Supply Voltage 
Switch
Output 
Voltage 
The problem: To generate a staircase waveform of	 will remain open (conducting) during a timing pulse 
high step uniformity, low step droop, and fast tran- 	 only as long as the emitter voltage remains greater 
sition time using low input power and no feedback.	 than the base-emitter threshold. This RC circuit is 
The solution: Transferring a charge from an input designed, based on the low saturation resistance of the  
capacitor to an output capacitor in such a way that 	 transistor, to decay within the duration of any reason- 
able timing pulse. The discharge of C 1 results in a 
the transferred charge is independent of the state of 	 pulse of collector current that imposes a discrete 
charge of the output capacitor. Equal step increments	
charge on the output capacitor C 2 and produces a 
are thereby achieved without feedback. Use is made of 	
corresponding step in the output voltage. The deple-
that property of a transistor whereby the collector	 tion of the charge on C 1 results in a quiescent cutoff 
current is proportional to the current flowing in the 	
condition in the transistor that continues through 
emitter circuit and independent, over a substantial termination of that timing pulse to the point in the 
range, of collector voltage, 	 following pulse at which C 1 again is discharged. When 
How it's done: A capacitor C 1 is added to the emit-	 the switch moves to position 2, the resulting rise in 
ter circuit of a conventional gating stage as shown in
	
base voltage unclamps the emitter voltage that rises as 
the illustration. The resistor is large enough to make	 C 1 charges through the resistor toward the supply 
C 1 the sole power source for the transistor. Since the 	 voltage. Since steady state is achieved well in advance 
energy stored in	 is finite and discrete, the gate	 of the next timing pulse, the amount of charge stored 
(continued overleaf) 
This document was prepared under the sponsorship of the National	 this document, or that the use of any information, apparatus, method, 
Aeronautics and Space Administration. Neither the United States Govern-	 or process disclosed in this document may not infringe privately-owned 
ment, nor NASA, nor any person acting on behalf of NASA: A. Makes 	 rights; or B. Assumes any liabilities with respect to the use of, or for 
any warranty or representation, express or implied, with respect to the 	 damages resulting from the use of, any information, apparatus, method, 
accuracy, completeness, or usefulness of the information contained in 	 or process disclosed in this document.
https://ntrs.nasa.gov/search.jsp?R=19640000005 2020-03-11T17:06:11+00:00Z
in C 1 will be known and discrete. Thus the discrete 
increments made in the output voltage are indepen-
dent of the number of previous. charging pulses and 
unaffected by variations in timing pulse frequency. 
Notes: 
1. This circuit could be used to advantage in pro-
graming physical or biological experiments for 
display of a family of characteristics simultan-
eously on a CRT.
For further information about this innovation 
inquiries may be directed to: 
Technology Utilization Officer 
Goddard Space Flight Center 
Greenbelt, Maryland 20771 
Reference: B64-10007 
Patent status: NASA encourages commercial use 
of this innovation. No patent action is contemplated. 
Source: George D. Breen 
(GSFC-48) 
Brief 64-10007


Low-power transistorized circuit provides staircase waveform

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