SWITCHING LAMPS ON/OFF
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In the previous lesson we have drawn the first connections between two devices, one of which represented by a voltage generator and the other represented by a measuring instrument, the voltmeter.
This is just the beginning! We anticipate in this regard that during the following lessons we will analyze and simulate the circuits and connections typically used in electrical systems. In this lesson we will begin this topic with a simple circuit to turn on a lamp.
However, before starting this series of lessons dedicated to the simulation of electrical systems for residential use, it is advisable to learn some sequences of Proteus commands.
The first sequence of commands to be addressed concerns the “cleaning” operation aimed at deleting all the devices and connections drawn in the worksheet. We will take as an example the worksheet created in the previous lesson and illustrated in Figure 54.
To delete all the objects placed in this worksheet, a first possibility is to access the “Edit” menu (step 1 indicated in Figure 55) and select the “Select All Objects” item (step 2 indicated in Figure 55).
In this way all the components of our circuit (including the connections) will change color (red) to indicate that they have been selected (step 3 illustrated in Figure 56).
Simply press the “CANC” or “DEL” key on the keyboard to delete all the components and connections of the circuit and then obtain a clean worksheet ready for a new exercise (Figure 57).
Figure 55: Starting the sequence of commands for cleaning the worksheet.
Figure 56: Completion of the sequence of commands for cleaning the worksheet.
Figure 57: Appearance of the worksheet after removing all devices and connections.
In particular, we start this new exercise by placing a 12 Volt direct current voltage generator into the worksheet. We will not repeat in detail this procedure because it has been widely analyzed in the previous session, we just illustrate the main steps of this procedure through the following three figures.
Figure 58: Selection of the single-cell battery.
Figure 59: Starting the battery configuration procedure.
Figure 60: Changing the battery voltage from 1.5 V to 12 V.
We recall that the voltage preset used by Proteus for the single-cell battery is 1.5 V. If we need a 12 V DC generator, we must click on the voltage value next to the battery circuit symbol (step 1 shown in Figure 59) in order to access the string field which contains the value of 1.5 V (step 2 indicated in Figure 59). Then we can modify this value by typing the required 12 V voltage (step 3 of Figure 60) and finally click on the “OK” button to confirm the changes made (step 4 of Figure 60). Once this procedure is completed, the worksheet will look as shown in the following figure.
Figure 61: Appearance of the worksheet after placing and configuring the 12 V battery.
It is not necessary to change the label associated with the voltage generator and we can therefore continue by inserting a device widely used in electrical systems: the lamp.
For this purpose, as shown in Figure 62, we select the item “Pick Parts” from the “Library” menu or alternatively we can press the “P” character on the keyboard.
Figure 62: Starting the procedure for searching and inserting a lamp in the worksheet.
Once the window with the list of devices is opened, as shown in Figure 63, we select the item “Optoelectronics” from the “Category” section (step 1 of Figure 63) and then select “LAMP” from the list of devices that appears once the “Optoelectronics” category is selected (step 2 of Figure 63).
An important aspect concerns step 3 of Figure 63 which indicates the description of the type of lamp, “Animated Light Bulb”, which reflects the fact that the simulated lamp is “animated”. We therefore expect that during the simulation it can somehow indicate its status (on or off).
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Note that on the right of the screen (step 4 of Figure 63) we see the circuit symbol that will be associated with the lamp. Well, we are now ready to confirm our choice by pressing the “OK” button as indicated in step 5 of Figure 63.
Figure 63: Completion of the procedure that searches and inserts the lamp in the worksheet.
Once the search and insertion of the lamp in the worksheet has been completed, it will appear as shown in the following figure.
Figure 64: Appearance of the worksheet after placing the lamp.
We can now proceed by drawing the wires that connect the devices. We will use the method already explained in the previous section: starting from the battery, with a series of mouse clicks we are able to draw the electrical connections between the battery and the lamp as indicated in the following two figures. In this way, we obtain the final circuit which connects the battery terminals to the two terminals of the lamp.
Figure 65: Drawing the battery to lamp connections.
Figure 66: Appearance of the worksheet after drawing the electrical connections between the battery and the lamp.
The circuit is thus ready to be launched in simulation. Before starting the simulation we notice that the lamp is currently off.
To launch the simulation, we press the “run” button (point 1 of Figure 67) and immediately we see the lamp changing its appearance with an animation that is sufficiently clear to indicate that the lamp is on (point 2 of Figure 67).
Figure 67: Starting the simulation of the battery-lamp circuit.
It is important to note that next to the lamp symbol there is the label “L1” which uniquely identifies the component in the circuit. Next to the lamp symbol we also read a voltage value of 12 V which indicates that the lamp used in the circuit works with 12 V and then should be supplied with 12 V.
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However, nobody can prevent us from inserting into the circuit a voltage generator operating with a voltage different from 12 V and it is therefore interesting to check how the simulator reacts to this situation.
Well, to get rid of this curiosity we have summarized in a single screen six different simulations that start from a 0 V voltage generator and then move to 1 V, 5 V, 10 V, 12 V and finally to 120 V with the clear intention to go beyond the nominal operating voltage of the lamp (see Figure 68).
We note that going from 0 to 12 V, Proteus uses a graphics that clearly wants to simulate the different level of light intensity emitted by the lamp when the supply voltage changes. In particular, the lamp appears switched off with 0 V and appears with its maximum brightness when it is supplied with 12 V. The simulator, on the other hand, does not report any anomaly when the lamp is supplied well beyond its nominal operating voltage. On the contrary, in real cases we know well that beyond a certain voltage value the lamp is damaged!
Figure 68: Simulations performed with various levels of voltage applied to a 12 V lamp.
With this last observation we conclude this lesson by leaving to the most interested readers the test, on their Proteus installation, of the circuits depicted in Figure 68.
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