Created it, 06/10/19
Update it, 06/10/24
N° Visitors
In the first part of this practice, you will continue the construction of your digilab, while adding beside the chart of the printed circuit used in the preceding experiments, a special plate for breadboard constructions called BREADBOARD (matrix or plate with 840 contacts which you can find in the various stores specialized in electronics) which will extend considerably the use potential of the digilab.
You then will carry out a series of experiments with which you will supplement your knowledge of the rockers and will examine in particular the operation of rocker J.K.
By using the rockers in your possession, you will carry out finally two simple circuits of application.
1. - PREPARATION OF THE MATERIAL
In this practice, you will use the following material :
1 box for the digilab (35 x 19 cm)
1 separation for the box of the digilab
1 front aluminum face for the box (17 x 18 cm)
1 plate or matrix of 840 contacts “Breadboard” (16,5 x 5,5 cm)
1 self-stick label of the connections of the matrix with 840 contacts (sold with
the matrix)
8 self-tapping screws of 2,2 x 9,5 mm
4 capscrews milled q 3 x 14 mm
4 nuts q 3
1 integrated circuit CD 4042 or its equivalent
2 integrated circuits MM 74C00 or its equivalent
1 integrated circuit MM 74C04 or its equivalent
1 integrated circuit CD 4027 or its equivalent
1 integrated circuit MM 74C08 or its equivalent
2 integrated circuits MM 74C74 or its equivalent
1 braid of black insulated canned wire
1 braid of red insulated canned wire
Let us see which are the characteristics of the matrix with contacts.
1. 1. - MATRIX
A CONTACTS
The matrix with contacts (figure 1-a) is a plate especially studied to allow the very fast realization of experimental electronic assemblies without having to resort to the use of the soldering iron. It consists of a synthetic insulating matter base, in which a matrix of 840 contacts to springs of high quality is built-in. These contacts are accessible from outside through as many holes of opening bored on the insulating support. These holes are with the standardized step of 2,54 Misters.
The matrix with contacts makes possible the insertion of all the electronic components, those discrete whose terminals have a maximum diameter of 0,8 mm like those integrated in T05 cases, DIL or DIP from 8 to 64 pins.
The contacts are out of noncorrosive nickel money alloy and each one of them is guaranteed up to 10.000 cycles of insertion by using wire 0,6 mm in diameter. The nominal resistance of each contact is 5 MW, while inductance and the stray capacity contact with contact are negligible up to 30 MHz.
The various contacts of the matrix are gathered between them as indicated on the label self-stick and represented figure 1-b.
In the central zone, there are 128 groups of 5 contacts electrically connected to each other and laid out in column (64 groups above and 64 groups below the median groove practiced on the support).
The integrated circuits can be inserted into horse on the central groove as you can see it on figure 2. The matrix can receive thus to eight integrated circuits DIL into 14 pins and for each one of those, there remain four contacts available to carry out the electric connections.
There are then eight groups of contacts, each one made up of 25 contacts electrically connected, laid out on line in the direction length on the two sides of the matrix as you can also see it with the figure 1-b. They are intended for power supply, mass and various the order links of the principal circuits assembled on the central zone of the matrix.
IMPORTANT NOTE :
The duration and the reliability of the contacts of the matrix are subordinated to the observation of the following standards of use :
never insert in a contact of the drivers or
terminals of components having a diameter higher than 0,8
mm because they could easily damage the springs of the contact.
you always ensure that the ends of the drivers or
terminals of the components to be inserted in the contacts of the matrix are not
damaged by folding, scratches or by residues of welding.
by carrying out the connections, exert a correct
pressure so that the ends of the drivers (or terminals of the components) are
introduced perpendicularly into the site of each contact and remain maintained
by the internal springs, thus guaranteeing a good electrical contact.
After these notes of introduction, you can take again the assembly of the digilab.
2. - ASSEMBLY
OF THE DIGILAB
Work consists in laying out on the box the printed circuit of the digilab and the front face on which the matrix will be fixed as well as the self-stick label reproducing the connections between the contacts of the matrix. Figure 3 illustrates how presents the digilab once the finished assembly.
Thus carry out the assembly by conforming you to the following instructions :
a) Unscrew the four screws blocking the provisional feet of the printed circuit of the digilab.
b) Take the box of the digilab and supplement it while assembling the separation in a way illustrated by figure 4.
c) Make pass the two cords of food of the printed circuit through the opening practiced in the separation and fix the printed circuit on the box in the position illustrated by figure 5, by means of four self-tapping screws of 2,2 x 9,5 Misters.
You must now fix the matrix and the self-stick label on the metal front face of the digilab. The latter, as you can see it on figure 6, is equipped with twenty-two holes ; four of them laid out with the angles are used to fix the front face on the box, six are used to fix the matrix, the six others can be used to fix an additional matrix which could be added if you would wish to increase the possibilities of the digilab later.
The site reserved for this second optional matrix will be occupied by the self-stick label which represents, like that was said, internal connections between the contacts of the matrix.
The remaining holes, being inside the rectangle screen printed on the lower part of the front face, will be used in a later practice when the digilab is supplemented by the assembly of the food on sector.
d) Take the matrix, lay out it on the higher part of the front face, so that the clamp holes of the matrix are in correspondence with those present on the front face. Fix the matrix on this one by means of the four screws q 3 x 14 mm at milled head and of four nuts q 3 to lay out with the four angles as you see it figure 7.
The two holes in the center of the matrix must remain free for the moment.
e) Take the self-stick label representing the connections of the matrix, detach the sheet of protection of adhesive surface and stick it on the front face, just below the matrix by positioning it in correspondence with the six holes of the front face, exactly as if it were about one second matrix (figure 8).
With this manner, the six holes which would be used to fix one second matrix are covered and at the same time you have the advantage of having constantly under the eyes connections between the contacts of the matrix. This will be particularly useful for you in the beginnings, as long as you will not have acquired yet a sufficient experiment in the use of the matrix with contacts.
f) Finally make pass the two crocodile clips of the cords of food of the printed circuit by the largest hole of the front face (that in bottom on the left), and fix the latter on the left opening of the box by means of four self-tapping screws of 2,2 x 9,5 mm as you see it on figure 9.
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