Practice to realise a voltage multiplier, using a source of alternating signal, or as it says to the band ac/dc, high voltage
The objectives of this first activity of the electronics module we can enumerate them as:
- To take contact with the electronic schemes
- To know the process weld of low temperature with tin and soldering iron
- To introduce the real operation of component assets (diode) and another liabilities (Condensing)
- To investigate on causes of possible failures in the operation (they do not specify themselves so that the student does not have tracks)
- To relate the factors of tension and current in a process where these variables increase (the tension).
- To study the use that this type of circuit has in the daily life (racket of mosquitos, fence for animal, etc)
This activity, although can be done with some of the simulators that we know (cocodrile, proteus. ) he is advisable to do it, since the process weld is fundamental that the utility is known by the student, given that it has in all the modules of the cycle. We happen to set out the passages for its accomplishment.
Before doing this first activity, is advisable to realise some brief exercises with the program that we are going to use, in our case crocodile. these activities are the following:
IMPORTANT. To open to Open office and to be keeping the activities that announce in this practice. The archives that are created by the program will have to be kept in the same folder that contains the memory.
- To mount a circuit that in series has three resistance of the same value. To measure the tensions that fall in the tips of the resistance
- To do just like point 1, but varying the value of the resistance.
- In series to mount a circuit with a diode and a condenser. To visualize the signal that we have to the entrance (generating) and the signal that there is in tips of the condenser. Taken care of where we put the mass.
- Now we will mount a similar circuit, but we are going to see as it influences to put a battery in the middle. In this case, we do before just like, and we measured where it shows the sounding with the mass down. Then, to change the mass in point b
1 Veremos a little theory of how multiplying works, with the premises of which the components that we used already have been studied in theory.
We will see as a tension in a simple circuit with a sine generator of 10 volts can be doubled.
This circuit is mounted with crocodile. We happen to explain it.
The resistance of 100 Ohms, is only after limiting the current of load of the condenser. We have a first step that is the moment that appears the positive cycle in the part superior of
generator. Then, one is going away to load the condenser superior thanks to the direct polarization of the horizontal diode. The scheme that we have is the following one
In this case the condenser is going to take the maximum tension from the generator, that is 10 volts, with the positive pole in the part superior (plate of above of the condenser)
In the second case, now it appears the negative cycle above (and therefore, the terminal of under the generator has a positive tension). In that case, they are going to work the vertical and condensing diode of down. we have the following equivalent circuit
Now the condenser to 10 volts with the plate of above positive is loaded.
The result are two put condensers in series whose tensions are added, 10 + 10 = 20 volts. We already have our doblador.
The first activity that we must do is
- To install the program crocodile in our PC
- To mount the scheme superior and when coming out to put two measuring tweezers or soundings (probe) to the entrance of the generator and of the circuit. It is necessary to have well-taken care of because the soundings take the measurement with respect to the mass, that there is to put.
- To visualize the signals in the program, using the tool that it is indicated
- It responds. With this circuit, it is possible to continue multiplying the tension, repeating the process?
2 Pasamos to now simulate another circuit similar to the previous one. In this case we can begin seeing a video where a triplicador is explained.
If they have been doubts, we return it to explain. If there are no doubts, to pass to activity 2 the circuit necessary to pass of a tension to three times the tension, is the one that we showed upon these lines. Three soundings have been put to indicate as the tensions with respect to the mass evolve. The blue one is the exit of the generator (sine of 10 volts of tip). the following one is the red one and we already have a maximum tension of 20 volts. This can take to confusion. The first cell, composed by C1 and D1 is in charge to load the condenser to the maximum possible tension. That tension is 10 volts, because it is the principle that can offer the generator. Therefore, once loaded the condenser to 10 volts, this one it remains loaded indefinitely. The reason reason why raises from 0 20 is due to how we are measuring the tension, from mass to the loaded plate positively. As we have two elements in series, the tension adds and is moments where the generator offers 10 volts, therefore, -10 but 10 = 0.
Soon we have the C2 condenser, that load with 20 volts, that is the maximum tension of the generator next to the load of C1, This takes place thanks to the positive polarization of the D2 diode
The third step is how C3 load. For it, we have to do what diode is polarized in direct and how the current is closed. If we phelp attention to the circuit, the diode that can lead is D3 and, therefore we have a circuit of load of C3 made up of the generator, C1, C3, D3 and C2, that is to say, enmeshes of outside. If we added the tensions we have the fixed tensions of 10 volts of C1, the one of 20 Volts of C2 and the variable of the generator. As C1 has a tension that contributes to remain in the load, we have a tension of effective load of the condensers of 10 volts, that there are to add with the tension with which it contributes the generator (10 volts) that gives a total of 20 volts.
- To mount a circuit with the same program that multiplies the tension 9 times
- When coming out to put the soundings to the entrance and with the mass in the part inferior of the generator.
- To visualize the tensions that give the soundings us
- To change to the mass to the terminal superior of the generator. How they change the signals?
Activity 3. We happen to mount the circuit actually
- On a plywood table, to draw the circuit of activity 2. To consider the distances in the drawing whereas clause the lengths of the components
- To puncture a thumbtack in the tie points of the components.
- To read the following point well on weld, but before doing it, you can practice welding loose cables. of this form, when we have the optimal results, we happened to realise welds in the pr¡tica
- In order to create the weld, to join the components that go united, to apply to heat to the set, prioritizing the great body but to warm up, that in this case is the thumbtack. Once he is hot, tin is applied to the union so that tin melts and a shining layer of weld forms. This process to apply tin and to form the weld ball usually lasts 2 or 3 seconds. If we went with time, resins spoil that the tin alloy brings and the weld is not well.
- Once finished all the assembly, to connect the generator of entrance and the terminals of exit.
- To verify that, when uniting the exit cables, a small spark takes place. The electrical arc will be greater in the measurement than we continue adding condensing and diodes.