Generator has an improved circuit for generating a controllable, high voltage spark having a constant known energy output. It can be used for testing the flash and ignition characteristics of nonmetallic materials in a controlled gas environment

Pippen, D. L.

English

NASA Technical Reports Server

October 1969	 Brief 69-10548 
.
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical 1nformation, Springfield, Virginia 2215 1., 
High Voltage Pulse Generator 
Power Input Stage
	
Output Stage 
----------------------------
Input Terminal	 Magnetic Core, Step-Down 	 I	 Spark Gap Power Transformer  
Switch LLJI Lt±II 
Input Terminal	 r	 ,	 Single Throw	 ,	 - 
- - Silicon Controlled Relay	 Rectifier I HHJ
Lamp 
Auto  
Manual 
L____.____---------------------- I
 Control Stage 
. 
The high voltage pulse generator contains a new and 
improved circuit for generating a controllable, high 
voltage spark having a constant known energy output 
for testing the flash and ignition characteristics of 
nonmetallic materials in a controlled gas environment. 
The majority of prior art systems designed to produce 
a high voltage spark relate to automotive ignition 
circuits. Other discharge or spark-producing circuits
have been designed for use with flash tubes which are 
fired by a high voltage spark. However, in these prior 
art systems, the emphasis has not been directed to-
ward production of a controlled, fixed energy spark; 
consequently, these circuits include no means which 
would insure a fixed energy discharge, or which would 
indicate the presence of a predetermined,
 voltage 
across a dischargeable capacitive circuit.
(continued overleaf) 
.
This document was prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the UniteØ States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19690000518 2020-03-16T18:08:54+00:00Z
The high voltage pulse generator is illustrated in the 
schematic circuit diagram. A capacitive discharge 
circuit is employed to produce a controlled, high volt-
age, fixed energy spark. A fixed voltage for the spark 
discharge is provided by a storage capacitor connected 
in parallel with a zener diode. Discharge of the capaci-
tor through the primary of an output transformer is 
controlled by a separately powered control circuit 
which employs a silicon controlled rectifier (SCR) as a 
switching device. A zener diode in the - control circuit 
is subject to the storage capacitor voltage; when the 
desired capacitor voltage is reached, the diode is 
driven into conduction to fire a second SCR in the con-
trol circuit; this in turn activates a relay to energize 
a ready lamp indicating that the circuit is prepared to 
deliver a fixed energy spark. The charge circuit is 
manually fired by closing a switch, or is automatically 
fired each time the circuit is prepared to deliver the 
fixed energy spark by linking the swit'ching mechanism 
to the relay. After each discharge, the first SCR is 
automatically commutated by the back EMF of the 
output transformer, and the second SCR is commu-
tated by the ac input to the control circuit.
Notes: 
I. The unique features of this invention include the 
provision of an automatic discharge control which 
operates only when the proper spark-producing 
voltage is present, and the provision of means for 
fixing an exact voltage across the storage capacitor, 
and indicating the presence of such voltage by a 
signal. 
2. Requests for further information may be directed to: 
Technology Utilization Officer 
Manned Spacecraft Center 
Houston, Texas 77058 
Reference: TSP69-10548 
Patent status: 
This invention is owned by NASA, and a patent ap-

plication has been filed. Royalty-free, nonexclusive 
licenses for its commercial use will be granted by
NASA. Inquiries concerning license rights should be
made to NASA, Code GP, Washington, D.C. 20546. 
Source: David L. Pippen 
Manned Spacecraft Center 
(MSC-12178)
. 
Brief 69-10548	 Category 01


High voltage pulse generator

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