Preparation of the
material |
Controlled
food of Digilab |
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Created it, 06/10/19
Update it, 06/10/27
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In the first part of this practice, you will carry out the assembly, then the test of a controlled food. This food, perfectly integrated into the digilab, will advantageously replace the pile used until now.
Then, you will continue the study of the numerical components by examining the circuits with shift called usually registers with shift. In English terminology, the latter are called SHIFT REGISTER (or simply SHIFT).
The circuits with shift, formed by a series of rockers connected in cascade, one following the other, are very much used in the numerical data processing. It is the case in the transmission of information in the field of the communication. These circuits are also used as meters and memories.
1. - PREPARATION
OF THE MATERIAL
To carry out the assemblies and the handling envisaged in this practice, you need the following components:
1 mains transformer for digilab 220 Volts primary education and 9 volts secondary
1 rectifying bridge B 40C 3700 / 2200 or equivalent
1 printed circuit for the food of the digilab - Dimension : Length = 11,7 cm and width = 3,9 cm
1 cord of food to 3 wire, (length with your choice)
1 card bipolar sector with ground
1 fuse holder for frame (see figure 10)
1 fuse of 220 V - 250 mA
1 casing red greenhouse-wire for frame (see figure 9)
1 black casing greenhouse-wire for frame (see figure 9)
1 double switch for front face two ways two positions (see figure 10)
1 plug connector with three ways for printed circuit (see figure 8)
1 connector female with three ways (see figure 21)
3 connector blocks with two dominos (see figure 17)
2 threaded metal hexagonal spacers Æ 3 - length 9 mm
2 screws Æ 3 x 14 mm milled head
2 screws Æ 3 x 4 mm
3 self-tapping screws 3,5 x 9,5 mm
3 self-tapping screws 2,9 x 12,5 mm
2 metal discs Æ 6 x Æ 3,2 mm
4 metal discs Æ 9 x Æ 4,3 mm
1 star washer
1 ground thimble hole Æ 3,2 mm
2 eyelets with thimble hole Æ 4,2 mm
1 electrolytique capacitor of 4700 µF - 25 V
1 electrolytique capacitor with the tantalum of 4,7 µF - 10 V
1 ceramic condenser of 100 nF
1 resistance of 220 W 1 / 4 W - tolerance 5 % (red - red - chestnut - but)
1 red diode LED Æ 6 mm
1 support of LED (see figure 12)
1 roller of welding
1 black insulated rigid wire
1 red insulated rigid wire
1 cable clamp (see figure 20)
1 black flex-wire section 0,5 mm²
1 flex-wire red section 0,5 mm²
1 black flex-wire section 0,25 mm²
1 flex-wire red section 0,25 mm²
1 green flex-wire section 0,25 mm²
1 soupliso Æ 2 mm
1 soupliso Æ 3 mm
1 integrated circuit LM 340T5 or equivalent
1 integrated circuit MM 74C175 or equivalent
1 integrated circuit MM 74C164 or equivalent
1 integrated circuit MM 74C165 or equivalent
2. - CONTROLLED FOOD
OF THE DIGILAB
The controlled food that you will cable on the digilab makes it possible to obtain starting from the alternating voltage sector of 220 volts, a continuous tension of 5 volts. This perfectly controlled tension has a constant value, independent of the variations of the tension sector and current delivered by this same food.
Figure 1 illustrates the electric diagram of the controlled food. Let us see its operation quickly.
The tension of the sector is applied to the primary education of a transformer using a double switch. Fuse 250 mA protects the transformer against an overcurrent. The secondary delivers an alternating voltage of 9 volts. This tension, illustrated with the figure 1-a, is rectified by the bridge of diode DR1. Then, it is filtered by the electrolytique capacitor C1 of 4700 µF. That makes it possible to obtain on its terminals a tension continues whose pace is indicated to the figure 1.b.
As you can observe it, this tension is not perfectly constant, but presents a residual undulation.
Moreover, this undulation can increase if the current delivered by the food increases. If the tension of the sector varies, the average tension at the boundaries of the condenser also varies.
To mitigate all these disadvantages, you will use the integrated circuit LM 340T5 which is a voltage regulator. On pin 1, it is possible to apply a rectified and filtered tension included / understood in 7,3 volts and 35 volts. Pin 3 is the exit and delivers a tension of + 5 volts perfectly controlled. The maximum current at exit east of 1,5 A.
The condensers C2 and C3 prevent possible oscillations and filter the high frequency parasites. The indicator lamp with LED indicates if the food is under tension or not.
Regulator LM 340T5 has a circuit protective against the overloads and short-circuit them accidental on the outlet side of the regulator.
The fuse protects the transformer against a possible short-circuit due to the C1 condenser or the rectifying bridge.
We traced the printed circuit of food illustrated figure 2 in order to facilitate your tasks of practice. The printed circuit is relatively simple as you can see it.
Proceed to the various operations with much attention and care and conform you to the following instructions.
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