Experiment 1: LED Current IndicatorThe purpose of the circuit in the two pictures is to light up the LED light.
What is happening is that the wires from the battery are connected to the circuit board, so that when there are other wires or devices connected that go through the holes of the board, they all will need aligned with each other or else the circuit won't work. That is just basic. We are trying to make the circuit work by making the LED light glow. The main purpose is to use the resistor to measure the resistance to the current flowing in the circuit. How this is working, is that the battery wires flow energy to the LED light, to the extra wire, and through the resistor to make our circuit light up the LED light. They are all aligned with each other both vertically and perpendicularly so that the circuit board through the holes creates a loop of energy to go through all devices used in the experiment. And if they are all not alligned the way they are to make the circuit work, therefore, it won't. Why this is happening, is because we want the LED light to glow. This is important, because we are using electricity through small devices that can handle amounts of electricity, to make a circuit successful at it purpose, which at this point, is to light up the LED. With understanding what the Schematic Diagrams show us in an experiment through symbols, we can see the loop of the electric current that will be going on and off again and again as long as they are all connected on the circuit board. Experiment 2: LED Brightness ControlThe purpose of this experiment is to, as it says in the title of the experiment, control the brightness of the LED light.
What is happening, is a potentiometer is not only being used to control the brightness of the LED light, but also as a resistor as well, because the potentiometer contains 100K Ohms, while the other resistor that is needed for this experiment only has 100 Ohms. How the experiment works is doing the same alignment process with the potentiometer, but when the potentiometer is being adjusted to the right brightness, more or less Ohms is being used for controlling that brightness of the LED light. Why this is important, is because the LED light needs to be controlled is for particular reasons: for a light being too bright or too dim, and it shows us how the entire loop of electricity that was created is strong enough to withstand the amount of Ohms is being used from the potentiometer at a specific brightness. And our purpose for this circuit, was to observe how the potentiometer does its job by turning the The two pictures of the circuit board shows the difference to what the circuit looks like with the light really dim (top picture), and with the light really bright (bottom picture). Experiment 3: Light Activated LEDThe purpose of this experiment is to observe how a photocell works as a light sensitive resistor.
What is happening is that a photocell, light sensitive device, is being as a resistor to light up an LED light. How this is working is that because the photocell is light sensitive, it absorbs the amount of light in an area, and it uses that light to turn on the LED. A mistake that can be made and that can easily be fixed, is that on the circuit board, the photocell must be connected to the same side of the circuit board the LED is on so that there is a connection between the two. Otherwise, the light that the photocell is absorbing is being used for nothing as long as there is no connection. The reason Why this is important, is because we are testing how a photocell can be used to absorb light in a room so that it can turn on a light with no control device. Also, if you put your finger on the photocell, the LED light goes a little dimmer. it is based on how bright the light in the room / area is. Experiment 4: Storage Of ElectronsWhat is happening is that electrons are being stored in a capacitor, so that they can be passed on to power an LED light.
How it works is that the battery flows electrons to the capacitor that stores a lot of those electrons, so that when it is connected to the LED light, those electrons that was stored in the capacitor now flows into the LED. 2 other wires are connected as well as two resistors to the circuit so that there is some control in resistance in the circuit so that nothing goes wrong with flow of electrons from the capacitor, because capacitors can contain the same amount of electrons as a battery, but it is charged and is used a lot quicker than a battery, which is why it is need of resistance. Why this is important, is because we want to observe how a capacitor stores the flow of electrons while powering a device. We want to control the current and resistance of the circuit as well, and they way we do that, is to have resistors and extra wires in the circuit, so that there can be some "layer" into the circuit as shown in the schematic diagram, from the battery to the capacitor, and from the capacitor to the LED. During this lab, I made a mistake of not reading the part of the instructions that started with either a 10 uF capacitor or a 1oo uF capacitor compared to a 1000 uF capacitor and see this difference. The difference is that both the 10 and 100 uF capacitors do make the LED light up the way the 1000 uF capacitor does, except the 10 and 100 only light it and and when the battery is removed from the circuit after ten seconds, the LED immediately turns off, as for the 1000, it dims slowly. This shows how much more of electricity the 1000 holds than the 10 and 100. |
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Experiment 5: Speaker ActionWhat the circuit is doing is to make the Speaker transform electrical energy into sound waves.
How the speaker is doing that, is the wires that are connected to it have to be connected with the rest of the circuit as shown in the schematic diagram. How it physically was done, was the red (positive) wire is connected to the red (positive) wire from the battery through the breadboard. While the black (negative) wire from the speaker is connected to one of the two alligator connected together, and the other one touches the 10 Ohm resistor in the circuit to make noise. The speaker makes noise through energy when the one alligator clip touches the metal of the resistor back through the speaker because it is pressure of metal against metal making sound. Why this is significant, is because we are trying to make energy into sound. And we use the speaker connected with the rest of the circuit, and it is the vibration of the alligator clip and the resistor together reflected to make a crackling sound through the speaker, because the two metals are connected with the current of the circuit which is the electrical energy and as long as the speaker is connected with it all, it will reflect the sound through it. |
Experiment 6: Diode TesterWhat the circuit is doing, is using a diode, that takes current in a circuit as a one way gate.
How the circuit works with the diode, is that it is all dependent on the flow of the current, and what type of energy is being processed to go through the Diode. The current is going to the right direction in this circuit, which means that the diode must be facing that way too, otherwise it won't work. Why this circuit is significant, is because it is how we are using the two silicons in the diode, Type P on the Anode side of the diode, and Type N on the Cathode side of the diode. The flow is coming from the ride wire of the battery, which is positive. So the Anode side of the Diode must be facing the opposite way of the flow of the current to take it in, and for Cathode which is the negative side releases that current back to the rest of the circuit. * Anode is the positive side of the diode. It takes in the current in a circuit. * Cathode is the negative side of the diode. It releases the current that Anode takes in back out to the rest of the circuit, only for Anode to take it in again, and for Cathode to take it back out over and over for as long as the battery is plugged in, and as long as Anode is directly facing where the current will come in. * The two pictures I took of the circuit also show the direction where the Cathode side of the diode is facing. * Picture One shows Cathode facing to the left where the current will be flowing through Anode at the other side taking in the current so that it will come out the other way through Cathode. * Picture Two shows Cathode facing the other direction. Since that Cathode is negative, and the current is coming through the positive side of the battery, the current bounces back to the battery, making the circuit incomplete with the LED not lighting up. |
The Circuit is using a Thyristor, which is a lot like a Diode in having the Current low in one direction, but a Diode doesn't need to be activated by Positive Energy to activate a Light Emitting Diode to turn on.
The Thyristor turns on the LED by having the wires from all sides connect with extra wires to the Anode and Cathode sides of the Thyrsistor (Anode=Positive, Cathode=Negative). The third part of the Thyristor to the right is the Gate. And the wire that is connected to the 1K Ohm Resistor briefly touched the Gate and it turns on the Circuit and it stays on. This is important, because we see how a Thyristor works by using a gate to turn on a Circuit with everything else connected to it. * Thyristors (Or SCR [Silicon/ Semiconductor Controlled Rectifiers]) can handle tens to hundreds of amperes. Which is why the LED light easily turns on with a simple touch of the red wire connected to the 1K Ohm Resistor. * Like Diodes, Thyristors have Anode (absorbs positive energy) and Cathode (takes out negative energy). But Thyristors also have a Gate. As soon as the Gate receives positive energy outside of the circuit, it will turn on and it will stay on, because the rest of the Circuit is still connected and has all of those amperes flowing through it. * Now with the Circuit on, and with no Mechanical Switches, the only thing that can turn off the Circuit is to disconnect the Battery. When the Battery is disconnected, not only does the Circuit turn off then, but it will stay off when the Battery is reconnected. This is because that now there is no positive energy flowing until there is when the 1K Ohm Resistor wire touches it again. |
Experiment 8: NPN transistor CheckerThe circuit is using an NPN Transistor to amplify the electrical signals in the circuit to light up two LED's.
From the 220 Ohm Resistor to the Green LED,the Transistor takes in positive energy as well as at the red LED through the Collector and through the Base. So the Transistor is now polarized for positive to go through the Collector and Base, and for negative to go out through the Emitter. The Transistor amplifies it / controls it to flow to the battery where the current started out from. And when the (red) push button is pressed, that positive energy/ charge flows and the Transistor is what decides the intensity of the brightness of the lights. And the green LED is brighter than the red LED because there is more positive flow through the Collector than the Base, because the Base is a smaller current than the Collector. It is significant because we are using a transistor to control the electricity flowing through it based on how much energy is flowing. We see how there is more positive energy coming from/ into the green LED making it brighter than the red one with less positive energy flowing into the Transistor. * A mistake I made during this experiment was forgetting the importance and difference between devices that have either the color red or black, because a black push button released the negative energy or unbalanced the flow of charge or made the circuit do the opposite of what it is supposed to be doing. * Using a black push button, and with the battery connected, the lights were already on instead of off, and when I press on the push button, the lights turned off instead of on like how it is suppose to go working with the red push button that was successful in the circuit. |
Experiment 9: PNP Transistor CheckerThe Circuit is now using a PNP Transistor to turn on the two LED lights....
...But now, the polarity is being changed in the circuit from Positive charge to Negative, because PNP Transistors only allow for the Circuit to work if the Collector and the Base receive Negative energy. This is significant, because we see the differences how NPN and PNP Transistors work to function circuits that they are required in. In this case, it is to light up the two LED's. The Changes To The Circuit * Replace The NPN Transistor With The PNP Transistor. * The Red (Positive) And Black (Negative) Wires Had To Be Switched In Their Places. * The Short Lead Sides Of The LED's Had To Be Facing The Opposite Way From Experiment 8. * The Direction Of Both Resistors Had To Be Changed To The Opposite Way. |
Experiment 10: Transistor OscillatorThe circuit uses both a PNP and an NPN transistor to cary a current, making the speaker make a sound frequency / audio signal.
With both an NPN and a PNP transistor, that means that they are both controlling / amplifying the electrical signals along with a speaker and a 104Z ceramic capacitor, as wells as 120K and 10 Ohm resistors to make a high pitched sound through the speaker. That sound represents the sound frequency of the varying current inside. Hertz (Hz) are the units of measurement known to the frequency of varying currents. The oscillator built generates a signal of approximately 500 Hertz. This frequency is called an audio signal, because the speaker will make a sound that can be heard by the human ear proving to us that there is a frequency / signal there. |
Experiment 11: 555 IC TimerThe circuit is using a 555 IC Timer to make an LED relentlessly blink.
The 555 IC has 8 pins: The Ground, The Trigger, The Output, The Reset, The Control Voltage, The Threshold, The Discharge, and The Power Supply. It is made up of resistors and transistors which is why it makes it an oscillator. The other components in this circuit (the resistors, the 10uF capacitor and the LED) all have to be connected to 7 out of 8 pins of the 555 IC to work. There needs to be resistance in pins 3, 6 (that is needed to travel across to pin 2), in pin 7, as well as for pin 8. As for 1, the capacitor had to be connected to both pin 1 and 2 storing electrons and producing them in the circuit, and as for pin 5, it is left hanging doing its job to control the voltage while not being connected to any components. The significance is, we created a blinking light circuit, while learning how the 555 IC Chip / Timer works by doing what we have learned in Experiment 10 as an oscillator having two transistors together "fighting each other". By doing the circuit for Experiment 11, you learn by putting together the components and the jump wires as well into the 555 IC to make an LED blink. |
Experiment 12 (Student Free Choice): Automatic Night LightThe circuit is using both a photocell and a potentiometer to control the brightness of the two LEDs.
With the photocell, light will be charged through the circuit into the two LEDs. The amount of light charged for as long as it takes, at night, the LEDs will be turned on and will be bright. The potentiometer can adjust the brightness LEDs if they are too bright or too dim. Basically, this is almost the opposite of Experiment 3 in brightness. But with an NPN Transistor with its emitter taking out the positive energy to the photocell which almost changes the polarity of having the LEDs turn on when it is dark instead of when it is bright. The significance of this Experiment is that we are using the photocell again, but this time, we are charging the photocell for the brightness of the LEDs when it is night as an "automatic night light". A compare of contrast of the circuit with my finger off the photocell and with it on. ---> |
Experiment 13: Electronic MotorcycleThe circuit did a repeat of Experiment 10 by making an oscillator, but instead with an potentiometer to adjust the sound frequency.
Just like Experiment 10 with the oscillator, sound frequency or audio signal, two transistors, an NPN and a PNP transistor must be connected together to make this frequency. But with the 100K Ohm potentiometer, the frequency can be adjusted to either high or low, making it sound like a motorcycle accelerating or slowing down on the streets. All of the other components were connected to each other to make the sound frequency sound the way it is. Like with Experiment 11, all of the components must be connected to each other or to the main components of this circuit to function. The resistance from the resistors had to travel down to the two transistors and connected to the potentiometer, the 10uF capacitor is between the two transistors storing electrons and producing them in the circuit, as well as the speaker being connected to the collector of both the 3904 (NPN) transistor and the 3906 (PNP) transistor. The significance of this circuit is that we are performing Experiment 10 again, but with a different schematic diagram, with different resistance, with a different capacitor, and with a potentiometer to make the sounds of an electronic motorcycle. |
Experiment 14: Railroad LightsThe circuit is using a 555 IC chip to make two LEDs blink like railroad lights.
Just like in Experiment 11, the 555 IC is being used in the circuit to make not only one LED blink, but two. Each LED are opposite polarities. The white LED on the top is positively polarized. While the red LED on the bottom is negatively polarized. The third pin of the 555 IC is the outlet. This is important, because the rest of the pins on the positive side of the circuit passes down the positive energy through to the outlet, making pin 3 positive. When pin 3 is positive, the red LED will be forward biased (DC voltage deliberately applied), and the white LED will be reversed biased. Therefore, the red LED will light and the white LED will remain off. * With the battery connected to the circuit, the red LED is the first to glow, then after 1 full second the glow switches to the white LED for half a second and then back to the red LED only to do that loop for as long as the battery is connected to the circuit. The significance of the circuit, is that we are using the 555 IC again continuing to learn how it works, and how it explains electronic devices that are man made that we see that blink. |
Experiment 15: Wake-Up AlarmThe circuit is using a 555 IC to generate an audio signal that has a sound frequency that is dependent on the amount of intensity light brings to a photocell.
Like previous experiments with the 555 IC, all components must be connected to each other and with the IC for the circuit to function. With the 555 IC generating the audio signal, it is needed to be amplified by the NPN transistor for the speaker in the circuit to reproduce the audio signal. The significance of this circuit is that it is a light-sensitive alarm which means that the sound the speaker makes is only made when light touches the photocell in the circuit, because when darkness covers the photocell, the speaker remains silent. |
Experiment 16: Code OscillatorThe circuit is using a 555 IC to make an audio signal when the push button is pressed.
Like the previous experiments with the 555, all components must be together in the circuit. With an NPN transistor along with it to amplify the audio signal, and a push button to make the speaker perform the audio signal (a "clicking" sound) as a code oscillator. The significance to use the 555 IC again, and to perform and practice Morse codes. |
Experiment 17: English Police SirenThe circuit is using the 555 IC as a clock to perform a sound frequency through an audio signal like an English police siren.
With all components connected to the 555 as well as the 220 Ohm resistor to the base of the NPN transistor, a tone from the sound frequency will be heard when the battery is connected. But that is when the push button is not pressed, when it is pressed, there will be a parallelism between the 470K and the 120K resistors. It will have a resistance value different from the one 120K resistor. Therefore, the frequency of the audio signal will change and a second tone will be generated by the 555 IC. These two tones of the sound frequency from the 555, makes the sound a lot like an English police siren. This is important, because we can tell how not only English police sirens, but perhaps all sirens make their sounds. However, sirens today do not have push buttons to make them sound the way they do, that might be the soul purpose of another circuit if there is one that doesn't involve a push button like this one. |
Experiment 18: Space Machine GunThe circuit is using a 555 IC to generate the sound of a phases gun like from space arcade games.
The way how it works is just like all 555 IC circuits. But the difference in this one, is that the polarity is changed. Throughout the circuit, the directions of the resistors are all over the place, but together they all work with the amount of resistance they all contain (47 Ohms, 100 Ohms, 1K Ohms, 3.3K Ohms, 6.8K Ohms, and 120K Ohms). It is also filled with capacitors that each contain and produce flow of electrons in the circuit. The other important difference in this experiment is that there are not only one, but two oscillators being produced in the circuit. One of them is controlling the frequency of the other. The significance of this circuit is to use the 555 IC again but in a different polarity, and it is also to use so many devices in all of the previous circuits just to make a sound like the ones made in arcade games. |