Electrical continuity scanner automatically scans 50 wires in 2 seconds to correlate all wires in a circuit with their respective known ends. Modifications made to the basic plan provide circuitry for scanning up to 250 wires

Boulton, H. C.

Diclemente, R. A.

English

NASA Technical Reports Server

December 1966	 Brief 66-10605 
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 Information, Springfield, Virginia 22151. 
Electrical Continuity Scanner Facilitates Identification
of Wires for Soldering to Connectors 
Magnetic	 Input 
Latch
	
28 V.D.C. 
Relay
Off
,.\ Search 
Indicator 
Lamps 
1-10,11-20.21-30 
31-40,41-50 
00/0 
0 Or- I
0000	
000	 0oo	 0000
Indicator 
Lamps 
1 t 10 
Terminal
ito 10	 ii to 20	 21 to 30	 31 to 40	 411050 Strips
AUTOMATIC ELECTRIC RELAY, 6-DECK 11-POSITION 
The problem: 
In the development of electronic equipment, circuits 
may contain from 10 to 250 wires, each of which must 
be correctly identified. In assembling the circuit, 
often the first end of each conductor, or wire, has 
been attached to a known "primary" terminal or pin,
the wires are bundled and routed in the desired con-
figuration, and spot tied or laced to retain the desired 
appearance through most of the routing. The alternate 
"secondary" conductor end must then be identified 
with its "primary" to determine its proper end termi-
nal point. For production runs, each wire is usually 
-	 (continued overleaf) 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19660000603 2020-03-11T17:45:06+00:00Z
stamped with a number or otherwise labelled to facili-
tate identification. For experimental work continuity 
is usually checked with an ohmmeter, "buzz-box," or 
other' means of indication of continuity between two 
points. This method is slow, tedious, and expensive. 
The solution: 
A electrical continuity scanner that can scan 50 
points in 2 seconds, automatically searching for con-
tinuity. 
How it's done: 
One known point is electrically connected to the 
common post of the electrical continuity scanner with 
a temporary jumper wire. Actuation of the switch to 
the search position will cause rotary relays to step, or 
search, until a circuit having electrical continuity is 
reached, or the search switch is released. This auto-
matic stepping is accomplished through use of con-
tacts provided on the automatic electric relay (RI) to 
make it free running when desired. After 10 positions 
(10 wires) have been scanned, a second automatic 
electric relay (R2) (not shown) is actuated I position 
by latching relay (Li) to transfer the circuitry to the 
next 10 circuits. In this manner 5 decks with 10 posi-
tions may be used to accomplish scanning of 50 cir-
cuits in a fully automatic or free running manner. 
When continuity is attained, a current of approxi-
mately 0.3 ampere at 28 volts dc will keep the relay 
held in, preventing further search, until observation of 
the indicator lamps indicates the number of the post 
providing continuity. The search switch may then be 
released and the known end point noted, with the 
post number providing continuity. The jumper wire is 
moved to the next known point and the search pro-
cedure is repeated until all wires in the bundle have 
been correlated with their respective known ends.
Notes: 
1. Modifications can be made to the basic plan to 
provide circuitry for scanning up to 250 wires. 
Digital readout of numbered positions can be 
readily provided. 
2. The wires to be tested can be used without strip-
ping or damage to the insulation if special test 
leads are constructed by soldering steel phono-
graph needles to mini-gator clips. 
3. One electrical continuity scanner has been con-
structed with the relays and circuitry inside a 
chassis box 10 inches by 6 inches by 3 1/2 inches, 
with terminal strips for 50 circuits, a common post, 
and 2 power input posts on top. Input power to 
drive this scanner was less than I ampere at 28 
volts dc. 
4. The scanner can also be used for the rapid fabri-
cation of multiwire electrical cables by minimizing 
termination errors prevalent with prior methods of 
wire identification. 
5. Inquiries concerning this invention may be di-
rected to:
Technology Utilization Officer 
Manned Spacecraft Center 
Houston, Texas 77058 
Reference: B66-10605 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C. 20546. 
Source: Ralph A. Diclemente
and Howard C. Boulton

of North American Aviation, Inc.
under contract to

Manned Spacecraft Center
(MSC-626) 
Brief 66-10605	 Category 01


Electrical continuity scanner facilitates identification of wires for soldering to connectors

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