Single electrical circuit component combining diode, fuse, and blown indicator with elongated tube of heat resistant transparent materia

Jenkins, K. H.

English

NASA Technical Reports Server

AT ION AL AERONAUT1 CS AND SPACE ADM 1 N 1 STRATION 
REPLY TO 
ArrN OF: GP 
D.C. 20546 
TQ : 
FROM 9 
SUBSECT o" 
USI/Scientific & Technical Information Division 
Attention: Miss Minnie organ 
GP/Qffice of Assistant General 
Counsel for Patent Matters 
Announcement of NASA-Owned 
U,S, Patents in STAR 
In accordance with the procedures contained in the Code GP 
to Code US1 memorandum on this subject, dated June 8, 1970, 
the attached NASA-owned U,S, patent is being forwarded for 
abstracting and announcement in NASA STAR, 
The following information is provided: 
U.S. Patent No, 
Corporate Source 0 
Supplementary 
Corporate Source 
NASA Patent Case No. z 
Enclosure: 
copy of Patent 
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w. 2 
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$ (NASA CR OR TMX OR AD NUMBER) 
Lh 
https://ntrs.nasa.gov/search.jsp?R=19710013320 2020-03-17T02:51:29+00:00Z
DIODE AND PROTECTION FUSE UNIT 
Filed March 5, 1965 
I 
17 
26, 32-1 
INVENTOR 
KEITH H. JENKINS I -'\ 
BY 
" ATTORNEYS I, 
6 
which has an indicator device incorporated therewith SO 
that should it become “blown” such condition may be 
readily ascertained. 
Accordingly it is an object of this invention to provide 
a diode fabricated from semiconductor material com- 
bined with a circuit breaking device. 
It is another object of this invention to provide a 
fused diode which is not attended by a bulky and rela- 
tively heavy separate circuit component. 
These and other objects and advantages of this inven- 
tion will be more apparent upon reference to the follow- 
This unit combines a diode, fuse, and “blown” indica- ing specification, appended claims, and drawings wherein: 
tor into a single electrical circuit component. The unit FIGURE 1 is a longitudinal side view of a cartridge 
includes an elongated tube fabricated from a transparent containing a diode and a fuse in accodance with the in- 
heat resistant material. Electrically conductive end caps 15 stant invention and showing the fuse in an unblown state; 
close the tube and layers of opaque material coat the in- FIGURE 2 is a longitudinal partly sectional view show- 
terior one third the length of the tube from each Of ing the components contained within the cartridge in the 
its ends. The diode and fuse wire are secured to the re- norma1 position for use; and 
spective end caps with a spring and indicator providing FIGURE 3 is a view similar to FIGURE 1 but show- 
an electrical connection between them. The indicator is 20 ing the condition of the cartridge according to the instant 
normally hidden behind the opaque material. If the fuse invention when the fuse wire has blown. 
wire melts due to an excess of electrical current, the In order to better understand the construction and use 
spring moves the indicator element to the transparent of as novel device, it will be described in relation to a 
portion of the tube. fuse element combined with a semiconductor diode. It is 
26 to be understood, however, that this novel concept will 
find application whene~er it is deemed desirable to  pro- 
vide circuit protection from shorting of a single com- 
ponent only as opposed to protection from a short at any 
point within the circuit. These other uses will be readily 
With continued reference to the accompanying figures 
wherein like numerals designate the similar parts through- 
out the various views, and with initial attention directed 
to FIGURE 1, reference numeral 10 designates generally 
Diodes fabricated of semiconductor material have found 35 a cartridge shaped container including a tubular portion 
12 fabricated from a transparent material such as glass 
10 A @T OF T 
The invention described herein was made by an em- 
PWee of the United States Government and may be 
manufactured and used by or for the Government of the 
United States of America for governmental purposes with- 90 apparent to those skilled in the art. 
out the payment of any royalties thereon or therefor. 
This invention relates to  a diode and more particularly 
relates to a semiconductor diode which is combined with 
a circuit breaking protective device such as a fuse. 
wide-spread application in electrical circuits especially 
where compactness and low power considerations are im- 
portant. For example, they are widely used as rectifiers 
in the secondaries of power transformers found in many 
types of communications equipment such as television and 40 
radio receivers. They have also been found to be useful 
in suppressing noise produced by arcing across the actua- 
tion switch of relays when the switcb is opened. the end cap 15 mounted at the opposite end of the tube 12 
latter application the diode because of its characteristic of is electrically connected to a fuse element or wire 2@ 
permitting only unidirectional current flow provides a low 45 which will melt when subjected to a current load higher 
resistance path for current produced by the collapse of than that which it is designed to carry in a manner well 
the magnetic field around the relay coil without affecting 
the normal current flow path, This diode is connected in 
parallel with the relay coil so that as the relay actuation 
switch is opened, the current produced by the collapsing 60 
field circulates through the diode and the coil until it is 
dissipated. Hence, no electrical charge builds up on the 
contacts of the switch which could cause an arc. 
When the diode is used in a manner similar t o  those 8,way from the fuse wire toward the diode. 
set forth above it is generally remote from circuit protec- 65 As illustrated, the i 
tive fuses or circuit breakers. It is easily seen then, that a electrically conductive 
short across the diode will result in an excessive load on that the indicator may 
the power source causing a main fuse or circuit breaker material with 
to open. Placing a fuse in the circuit with the diode, how- the fuse wire 20 running directly through it. 
ever, adds t o  the number of components, complicates wir- 60 The opposed 
ing, increases bulk and weight, and generally mitigates the with opaque la 
advantages originally obtained by the use of a semicon- ant paint, that extend approximately one third of the 
ductor device. tube length from each end to conceal a t  one end the fuse 
According to the instant invention it has been found wire 20 and the indicator 26, and at the other end the 
that the advantages inherent in the uses of diodes fabri- 66 diode unit 16. Thus, when an excessive surge of current 
cated from semiconductor material may be retained and passes through, and melts the fuse wire 20, the spring 22 
a circuit protecting fuse may be employed without the will pull the indicator 26 from behind the opaque layer 
attendant increase in bulk and weight which results from 3 at  one. end of the tube into the clear center third 32 of 
the use of a separate circuit breaking component. This is the tube 12 so that it may be readily seen by visual in- 
accomplished by utilizing a cartridge in which the diode 70 spection of the cartridge. As shown in W X J R E  3 the 
and fuse are both incorporated and connected into a com- indicator is painted a distinctive color, such as red, to en- 
pact circuit component. The fuse is preferably of a type hance its visibility. 
is fabricated from an 
t is obvious, however, 
The diode unit 96 may any of the usual types such 
as P-N junction, point contact, or metallic and of itself 
forms.no part of the invention. Current flow to the diode 
is provided through the tab 18 as one connection point 
and through another conductive external c 
unction 17 between the diode unit 
ince the fuse wire 2 is utilized to provide protection 
from a short within th diode itself, it is, as a rule of 
thumb, constructed so as to have twice the current carry- 
ing capacity of the diode. For example, if the diode is 
rated at 750 milliamps the fuse wire 20 should have a 
capacity of approximately 2 amps. 
An example of a circuit in which this diode fuse com- 
bination is found useful is the actuation circuit for a 
relay as described above. In order to prevent arcing across 
the switch which controls the ffow of current through 
the coil of such a relay and, therefore, suppress radio 
noise, the diode-fuse combination is placed in parallel 
with the coil. The diode is arranged such that little or no 
current will flow through it during the time the actuation 
switch is closed and current is flowing through the coil. 
In order to facilitate this positioning markings are pro- 
vided on the exterior of the cartridge BO as shown in 
FIGURES 1 and 3. As the actuation switch is opened the 
field collapsing around the coil produces a current Nhich 
flows in a direction opposed to that which would be con- 
sidered normal. This collapsing field will produce a 
charge on the open side of the switch which might cause 
an arc unless effectively dissipated. The diode prevents the 
building of a charge by forming a low resistance path 
for current through it and the coil thereby forming a cir- 
cular current flow which continues until the charge is 
dissipated. 
If the diode in such a circuit should become shorted 
and there was no fuse for protection, the remainder of 
the circuit would be rendered completely inoperative 
and therefore the relay would be put out of service. Where 
the fused diode of the instant invention is utilized, how- 
ever, the parallel circuit merely becomes open if the di- 
ode is shorted and the relay will continue to be operative 
even though there will be then some danger of arcing 
across the coil actuation switch. In a large rocket powered 
space vehicle system where there are literally thousands 
of relays and where it is very important that none of them 
fail, a fused diode such as that described herein is in- 
valuable. 
It will be apparent that by utilizing the teachings of 
this invention a circuit component combining the features 
of both a diode and a fuse can be produced. The combina- 
tion of these two features within one component great- 
ly reduces the bulkiness and weight required should sep- 
arate components be utilized. Obviously, savings in weight 
and bulk are very desirable in the design of all types of 
aircraft including rocket powered space vehicles. Further- 
more, the cost of the component mounting hardware and 
fabricating of the finished assembly will be considerably 
less than that obtainable under present methods. 
The invention may be embodied in other specific forms 
without departing from the spirit or essential character- 
istics thereof. The present embodiment is, therefore, to be 
considered in all respects illustrative and not restrictive, 
the scope of the invention being indicated by the append- 
ed claims rather than by the foregoing description, and 
all changes which come within the meaning and range 
of equivalency of the claims are therefore intended to 
be embraced therein. 
What is claimed and desired to be secured by United 
States Letters Patent is: . A device adapted to be utilized in an electrical cir- 
cuit comprising: 
(a)  a container 
(1  ) having a transparent portion and 
(2) including at least two electrically conductive 
(b) 0 diode, fabricated f 
points and 
a semiconductor material 
(1) electrically connected to one of said contact 
(2) disposed within said container; 
(c) a fuse wire, for opening the circuit through said 
( I )  electrically connected to the other of said 
(2) disposed within said container; 
(d)  an indicator held in a first position remote from 
said transparent portion by said fuse wire; and 
(e)  means for biasing said indicator toward said trans- 
parent portion whereby failure of said fuse wire 
causes said indicator to move to if second position 
and be displayed at said transparent portion. 
2. A device according to claim 1 wherein said means 
for biasing comprises a tension spring having a first por- 
tion held stationary to said container and a second por- 
3. A device according to claim 2 wherein said spring 
and said indicator care the electrical connection between 
fuse wire and said diode. 
A device adapted to  be utilized in an electrical cir- 
for controlling a flow of current, 
5 
diode should it become shorted, 
contact points and said aiode and 
" 
15 
20 tion attached to  said indicator. 
25 cuit comprising: 
(a) a container 
(1) having a transparent portion and 
(2) including at least two electrically conductive 
contact points insulated from one another; 
(b)  a diode, fabricated from a semiconductor mate- 
rial for controlling a flow of current, 
(1) having one portion electrically connected to 
one of said contact points and 
(2) disposed within said container; 
(c)  a fuse wire, for opening the circuit through said 
(1) having one end electrically connected to an- 
other of said contact points and 
(2) disposed within said container; 
(1) fabricated from electrically conductive mate- 
rial and 
(2) connected to the other end of said fuse wire 
whereby it is held in a first position remote from 
(e) spring means fabricated from electrically conduc- 
( €  ) biasing said indicator toward said transpar- 
ent portion whereby said indicator will be dis- 
played at said transparent portion upon failure 
of said fuse wire, and 
(2) connected to another portion of said diode to 
thereby, with said indicator, provide an elec- 
trically conductive path from said fuse to said 
diode. 
9. A device adapted to be utilized in an electrical cir- 
cuit Comprising: 
(a)  a tube fabricated from heat-resistant, transparent 
(1) layers of opaque material extending inward- 
ly from each end substantially one-third of its 
length to form a window at substantially the 
middle one-third of said tube, and 
(2) two electrically conductive contact points se- 
cured thereto; 
(b) a diode, fabricated from semiconductor material 
(1) having first and second externally electrically 
(2) disposed within one end of said tube; 
30 
35 
diode should it become shorted, 
40 (d) an indicator 
45 said transparent portion; and 
tive material 
50 
55 
material having 
GO 
05 
for controlling a flow of current, 
conductive contact points and 70 
(c) said first external contact point of said diode elec- 
tricallv connected to one of said tube contact ooints: 
(d)  a fisc wire, for opening the circuit through said 
contact points insulated from one another; 75 diode should it become shorted, 
(1) having one end nnected to the other of said 
tube contact points and caps; 
(2) disposed within the other end of said tube, 
(1) fabricated from electrically conductive mate- (i 
rial and 
(2) connected to the other end of said fuse wire 
whereby it is held in a first position hidden from 
view by the layer of opaque material on the end 
of the tube in which the fuse wire is disposed; 
and 16 rial, 
( f )  spring means fabricated from electrically conduuo 
(1) biasing said indicator toward said transparent 
window whereby said indicator will be dis- 
played in said transparent window upon failure 
of said fuse wire, and 
(2) connected to said second external contact 
point of said diode to thereby, with said indi- 
cator, provide an electrically conductive path 
from said fuse wire to said diode. 
. A device adapted to be utilized in an electrical cir- 
(a) an elongated tube of heat-resistanl, transparent 
material having 
(1) layers of opaque material extending inwardly 
from each end substantially one-third of its 
length to form a window at substantially the 
middle one-third of said tube, and 
(2) two electrically conductive end cap., one se- 
cured to and closing one end of said tube and 
the other secured to and closing the other end 
of said tube; 
(b) a diode, fabricated from semiconductor material 
(1) having first and second external electricdty 
(2) secured within d tube to one of said en 
(c) said first external contact point of said diode elec- 
ti-ically connected to said one of said end caps; 
(d) a fuse wire, for opening the circuit through said 
diode should it become shorted, secured within sai 
tube with one end attached to the other of said en 
aps; 
(e) an indicator 
(e) an indicator, 
( 1 )  fabricated from electrically conductive ma&- 
(2) connected to the other end of slid fuse 
whereby it is &Id in a first wsition hidden tive material 
cuit comprising: 
for controIling a flow of current, 
conductive contact points 
view by the layer of opaque makrial on the 
end of the tube in which the fuse wire is &- 
posed; and 
(f)  spring means fabricated from eIectrically conduc- 
15, 
tive material 
(1 
20 
fuse wire and 
(2) connected to said second external co 
3,179,853 4/1965 Kozacka ______--___ 3 
3,213,345 10/1965 Loftus __________..___ 


Diode and protection fuse unit Patent

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