Lab 1
What is it?
Our first lab was a circuit that used a 100 Ohm resistor and light emitting diode (LED) as its loads. How does it work? The electrical charge enters the circuit through the negative side of the 9 volt battery, where it travels into the LED through a wire to the resistor set at a resistance of 100 ohms. The circuit works by limiting the flow (current) of electricity in the circuit as through converting electricity into heat energy that can be felt when touching the resistor. Why is this important? This is important since too much electrical flow in a circuit could cause loads to overload and burnout in the circuit. by adding resistors, not only does it protect the circuit, but it can also be used to manipulate the strength of the load in the circuit as is seen done in lab #2. |
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Lab 2
What is it?
In lab 2 we add a potentiometer to the circuit that works as an adjustable resistor in a way as to limit the flow of current. How does it work? As the dial on the potentiometer is turned in direction, the current is low or stopped all together due to a higher resistance given out by the load, while when it is turned in the other direction, the current is allowed to freely move as little to no resistance is put on the current by the potentiometer.. Why is this important? Potentiometers can be seen used in radio knobs and desk fans and are used to control the strength of the load in a circuit, whether the load illuminates more or less, or moves faster or slower. |
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Lab 3
What is it?
in lab 3 the potentiometer is replaced by a photocell, another device that works similar it in the manner of manipulating the resistance in the circuit due to the effects of outside inputs, in this case the resistance is determined by the brightness of the area surrounding the circuit. How does it work? The photocell detects lighting in the area and controls its resistive values based off how much light there is in the room for example, one could be set to have a lower resistance the darker the room is (device will turn on in the dark), while another could be set to have a lower resistance in the light. In the circuit, the electric charge is repelled from the negative side of the battery through the LED where it emits light and travels to the photocell where the amount of current is determined by the light of the surrounding area of the circuit. Why is this important? Photocells are used to make daylight sensing lights that automatically turn off in the morning and reactivate at night. They can also be used to detect movement and activate a light or alarm (anti-burglar system). |
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Lab 4
What is it?
In Lab 4 we go back to using resistors and LEDs, only now we also have a capacitor built into the circuit that provides a brief amount of energy to the circuit after the battery is unplugged. How does it work? When the circuit is first attached to a powersource, some of the electrons fill up the capacitor, while others continue their route through the circuit. when the battery is turned removed from the circuit, the stored electrons leave the capacitor and re-enter the primary circuit re-activating the light for a short period of time before the storage tank (capacitor) fully depletes its supply of energy. Why is this important? Capacitors are important as they can be used to provide electricity to a circuit for a short period of time, reset or balance out any instabilities in a circuit, and convert alternating currents into a direct current power supply. |
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Lab 5
What is it?
This is a 9 volt battery powered speaker device. How does it work? The speaker rubs back and forth against the 10 ohm resistor, changing the flow of electricity through the speaker. As the circuit changes charges, the coil in the speaker is either attracted to or repelled by the electromagnet in the speaker, causing it to push or pull a cotton cone and create a noise. Why is this important? Speakers are used to communicate important information from a distance and or measure distance (sonar) they can be found in cell phones, computers, radios, and vehicles such as cars and submarines. |
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Lab 6
What is it?
It is a LED light circuit with an additional plain diode. How does it work? When the cathode is attached to the negative side of the circuit, a forward bias is created where the diode is used as a conductor, while when it is attached to the positive side of the circuit, the cathode will work as a resistor, slowing down the flow of current enough to stop a response from triggering in the loads attached in the circuit. Why is this important? Diodes can be used to convert AC energy into DC energy by limiting current access to one direction of the circuit. They can be seen used in wall-plug-in chargers. |
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Lab 7
What is it?
It is a circuit with an LED, 220 ohm resistor, 1K ohm resistor, and a SCR as its loads. How does it work? The gate on the SCR stops the current since there is no positive charge to open the gate, stopping the electrons from passing through the anode and completing circuit. Once the positive charge from the wire containing the 1k ohm resistor makes contact with the gate, the gate will open and remain open even after the wire is taken off the gate of the SCR, allowing the LED to now emit light now that the circuit is complete, the only way to turn off the circuit once this happens is to unplug the power source. Why is this important? A SCR is down to the basics, a Diode with a gate where it can convert AC into DC and work as a resistor and conductor, this creates a diode switch in a way that can be used to turn on certain loads in a circuit. |
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Lab 8
What is it?
It is a circuit with a 1k and 220 ohm resistor attached, alongside Two LED´s, a NPN transistor, and a pushbutton. How does it work? There are two currents involved in this circuit. There is a base current and a collector current, the base current is the weaker of the two currents and connects to LED 1, where it produces light, while the collector current is the stronger of the two and connects to LED 2 where it emits a brighter light than LED 1. This happens since the collector current amplifies itself off of the base current. Why is this important A NPN can be used to amplify certain loads in a circuit based off the input of charges in the base current. |
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Lab 9
What is it?
It is a circuit with a 1k and 220 ohm resistor attached, alongside Two LED´s, a PNP transistor, and a pushbutton. How does it work? Similar to how a NPN functions, a PNP transistor has a base and collector current, the only difference between the two is their polarity. In a PNP transistor, the transistor becomes correctly biased when the collector is connected to the negative side of the circuit while a NPN works the opposite way around. Why is this important? Both transistors are good for creating amplified/stronger loads or outputs in a circuit. |
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Lab 10What is it?
Lab 10 is a Transistor Oscillator. How does it work? The frequency is determined by the 120 ohm resistor and the capacitor, while the oscillation is kept and maintained by the speaker and NPN. Why is this important? The Oscillator is able to produce sound due to changes in current, meaning that the setup of the circuit generates a constantly changing current similar to a circuit timer, with out the need for one in the circuit. |
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Lab 11
What is it?
Lab 11 is a blinking light, a circuit with an LED, timer, capacitor, and multiple levels of resistors. How does it work? There is a 555 timer attached to a circuit with an LED as its primary load. The 555 timer sends out pulses of electricity throughout the circuit that cause the LED light to turn on and off in a constant blinking pattern the frequency of the timers pulse depends on the strength of the resistors and capacitors on the circuit with stronger resistors/larger capacitors having a lower pulse rate and smaller resistors and capacitors having a higher and faster rate of pulses. Why is this important? Blinking lights are often used to represent caution when driving or warnings near railroad tracks. Timers in circuits are also used in radios to generate pulses (changes in frequency) the the speaker interacts with to produce music or sound. |
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Custom Lab (Lab 12)
What is it?
It is a light activated alarm designed to work as an alarm clock. How does it work? The 555 timer generates a pulse thats strength is determined by the resistors used in the circuit and the amount of light collected in by the photocell, this pulse/change in frequency creates sound in the speaker that is usually high pitched due to the higher amount of current flowing through the circuit Why is this important? This circuit shows how a photocell can manipulate a load in a circuit as the more light the photocell collects, the higher the pitch of the speaker, while the less amount of light it collects, the lower the pitch the speaker generates. |
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Independant Labs
What is it?
It is a moisture detector that emits an LED light when moisture is detected How does it work? The circuit is broken by the two prongs attached to the circuit, once contact is made with the prongs and a surface of low resistance, the current is able to travel from one prong to the other, using the surface as a source to transport the current and complete the circuit. In this case, Moist soil is the surface with low resistance that we are using to transport our current Why is this important? While this circuits primary function is to alert the persons viewing the circuit of whether the soil is moist or not, it could also be used in real life when creating an alarm/signal for when a circuit system comes into contact with a conductive material that shortens out the circuit on accident. |
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What is it?
It is an audible morse code circuit. How does it work? There is a button attached to the circuit that stops the speaker/oscillator from making constant noises due to the feedback from the 555 timer by breaking the circuit until the button is pressed down and finishes the circuit, allowing noise until the button is released. Why is this important? This circuit shows how a button can be used to break a circuit and stop constant aspects from generating a constant output on the load. |
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What is it?
It is a light activated alarm clock. How does it work? Light comes into contact with the photocell, lowering the amount of resistance in the circuit and allowing the 555 timer to create small changes in current that produce sound through the speaker, until it is dark again and the resistance on the photocell goes back up. Why is this important? The light activated alarm clock works off of environmental feedback generated by the photocell, when it notices a change in the environment, the alarm begins to sound off, in this case the alarm is activated by lights, however, there could be a motion activated photocell used instead of a light activated to make a alarm system that works off motion, similar to the ones heard in stores when a person enters and exits a store. |
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What is it?
It is a water detecting Circuit that makes an audible noise when coming into contact with water How does it work? The circuit has two prongs that break the circuit until it comes into contact with the same bowl of water, allowing the current to flow through the water from one prong to the other, fixing the circuit and allowing the speaker to produce sound. Why is this important? An audible water detector can be used in dams to determine if there is an overflow or two much water in one area of the dam or the other, by notifying if there is too much water in one area by generating sound or other forms of output to notify dam workers. |
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What is it?
It is an automatic night light. How does it work? Attached to the circuit is a photocell that reduces the flow of current in a circuit when the lights are on, while increasing the flow of current when the lights are off, allowing the light to turn on in the dark. There is also a potentiometer that adjusts the brightness of the light so that it can be dimmer or brighter depending on the input from the user. Why is this important? The circuit uses two loads to control the LED lights within the circuit, the first load the photocell, makes it so that the LED lights dependent on the environment surrounding it, while the second load, the potentiometer, makes it so that the LED lights brightness can be controlled by the user to make it dimmer or brighter. |
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Lab 13 Safety Power Sources & Meters
What is it?
In this lab we measure Voltage and Amps in a circuit and how to safely measure circuits without causing a short circuit. How does it work? When measuring voltage, make sure to connect the two prongs across from one another on the circuit or load, for example, if you wanted to measure the voltage in a resistor on a circuit, you'd attach the prongs on corresponding sides of the resistor. When measuring Amps, the prongs should be connected to one another in series. Why is this important? It is important to know how to correctly use a multimeter on a circuit as to prevent damage to the person, equipment, and circuit, we also went over resistance in this lab with comparing the resistance of certain areas of the human body before and after being wet, with results showing lower resistance on wet skin. |
Lab 14 Sources of Electricity
What is it?
In the lab we look at different ways to gather electricity from our environment, specifically through heat, solar energy, and chemical reactions (batteries). How does it work? To harvest heat energy, we can use a thermocouple that collects heat and transfers it into electricity, to harvest solar energy, we use a solar cell that collects energy when it comes into contact with sunlight (our primary) source of solar energy. To harness chemical energy, we store chemicals in a battery where they convert into electrical energy. Why is this important? Depending on the environment surrounding us, it may be easier to resort to different form of energy than another, for example, the most useful source of energy in space may be solar energy due to the abundance of heat in space and increase in solar energy, while living in a warm-shaded environment where there is a source of heat such as a fire, hotspring, or volcano makes it easier to gather energy rather than solar energy. |
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Lab 16 Switches and Switching Circuits
What is it?
In this lab we used switches and buttons to open circuits and alter the flow of electrons. How does it work? One of two things would happen when we used the switch, either we would shut off the entire flow of electricity throughout the entire circuit by opening the circuit, or we would alter the flow of the electrons so that they´re transported to a different load while the other load turns off. Why is this important? This is important since it allows us to turn circuits on and off and create safety features that will stop us from shorting a circuit. |
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Lab 17 OHM´S LAW
What is it?
Ohm´s Law is the relationship between Voltage (E), Current (I), and Resistance (Ω/R). How does it work? Ohm´s Law is used whenever someone is trying to find the current, voltage, or resistance in a circuit through equations such as I= E/R, R=E/I, and E=IxR. Why is this important? It is important to know Ohm´s law as to prevent accidents from occurring such as not knowing how many volts of electricity are flowing through a circuit or how strong a certain resistor should be on a circuit as to prevent the voltage from frying the load due to it being over the loads capacity. |
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Lab 18 Power-Heat-Light
What is it?
I this lab we learn to measure power (Watts) alongside the formulas to solve for it and or other variables using Watts. How does it work? Watts (power) is equal to voltage times current or voltage squared divided by resistance. Power can also be solved by current squared times resistance, we use these formulas to predict the theoretical/expected amount of power in the circuit, however, sometimes there can be slight changes between the theoretical and actual power levels as in this lab we compare and contrast our theoretical answers with our actual breadboard results where we can see differences between the two values. Why is this important? This is important since watts represents the rate of doing work per a certain unit of time, it is how we measure how much power a circuit uses at a time, with the more power used at a time leading to a higher current and higher cost from a billing perspective. |
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