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Voltage

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Intros
Lessons
  2. What makes up a circuit?
  3. What does it mean by "series" and "parallel" configurations?
  4. What really is a battery?
  5. What is voltage?
  6. What is the Loop Rule?
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Examples
Lessons
  1. Finding Voltage in Series Configuration
    Calculate the total voltage drops across the resistors in this circuit. Explain how Kirchhoff's 2nd Rule applies here.

    Introduction to Waves
    1. Finding Voltage in Parallel Configuration
      Find the missing voltage drops across the two resistors in parallel (R2 and R3).

      Introduction to Waves
      1. Finding Voltage in BOTH Series & Parallel Configurations
        Find the missing voltages across resistors (voltage drops) for R2, R3, and R5. (Assume that R3= R5).

        Introduction to Waves
        1. Finding Voltage across Resistors and at Certain Points in More Complex Circuits
          1. Find the missing voltages across resistors (voltage drops) for R3, R6, R8, and R9.

            Introduction to Waves
          2. Find the voltage at each point (in comparison to the positive terminal).

            Introduction to Waves
        2. Finding Voltage in More Complex Circuits
          Find the missing voltages at each point and across each resistor (voltage drops).

          Introduction to Waves
          Topic Notes
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          Introduction to Voltage in Electric Circuits

          Voltage is a fundamental concept in electrical engineering, playing a crucial role in understanding how electric circuits function. Our introduction video provides a comprehensive overview of voltage, making it an essential starting point for anyone delving into the world of electronics. Voltage, often described as electrical pressure, is the force that drives electric current through a circuit. It's measured in volts and represents the potential difference between two points in an electrical system. This concept is vital for designing and analyzing circuits, from simple household appliances to complex industrial systems. The video explores how voltage sources, such as batteries or power supplies, create this potential difference, and how it affects the flow of electrons. By grasping the basics of voltage, students and enthusiasts can build a solid foundation for more advanced electrical concepts, making it an indispensable topic in any electrical engineering curriculum.

          Understanding Electric Circuits and Their Components

          Electric circuits are the foundation of modern electronics, powering everything from smartphones to household appliances. At their core, electric circuits consist of three main components: a battery, connecting wires, and devices or resistors. Understanding these elements and how they interact is crucial for anyone interested in electronics or electrical engineering.

          The battery, also known as a power source, provides the electrical energy that flows through the circuit. It has two terminals: positive (+) and negative (-). The connecting wires serve as pathways for the electric current to travel between components. These wires are typically made of conductive materials like copper, allowing electrons to flow freely. Devices or resistors are the components that utilize or control the electrical energy. Resistors, in particular, limit the flow of current in a circuit.

          When designing electric circuits, components can be arranged in two primary configurations: series and parallel. In a series configuration, components are connected end-to-end, forming a single path for current to flow. This means that the same current passes through each component in the circuit. If one component fails in a series circuit, the entire circuit is broken. Series circuits are commonly used in string lights, where if one bulb burns out, the entire string goes dark.

          Parallel configurations, on the other hand, provide multiple paths for current to flow. In this arrangement, components are connected across each other, with each having its own branch. The voltage across each parallel branch is the same, but the current can differ. Parallel circuits are more resilient than series circuits because if one component fails, the others can still function. This configuration is often used in household wiring, allowing multiple devices to operate independently.

          To visually represent electric circuits and their components, engineers and technicians use schematic diagrams. These standardized drawings use symbols to depict various circuit elements. For example, a battery is typically represented by a long and short parallel line, with the longer line indicating the positive terminal. Resistors are shown as zigzag lines or rectangles, while wires are depicted as straight lines. Schematic diagrams make it easier to understand complex circuits and troubleshoot issues.

          When working with electric circuits, it's important to consider Ohm's Law, which describes the relationship between voltage, current, and resistance. This fundamental principle states that the current flowing through a conductor is directly proportional to the voltage and inversely proportional to the resistance. Understanding Ohm's Law is crucial for calculating and predicting circuit behavior.

          Safety is paramount when dealing with electric circuits. Always ensure that the power source is disconnected before making changes to a circuit. Use insulated tools and wear appropriate protective gear when necessary. Be aware of the voltage and current ratings of your components to prevent overloading or damage.

          As technology advances, electric circuits continue to evolve. Integrated circuits, for instance, pack thousands or millions of components onto tiny silicon chips, enabling the creation of powerful and compact electronic devices. Despite these advancements, the basic principles of electric circuits remain the same, forming the backbone of our electrified world.

          Whether you're a hobbyist tinkering with Arduino projects or an aspiring electrical engineer, mastering the basics of electric circuits is essential. By understanding the roles of batteries, connecting wires, and resistors, as well as the differences between series and parallel configurations, you'll be well-equipped to explore the fascinating world of electronics. Remember to consult schematic diagrams when working on complex circuits, and always prioritize safety in your electrical endeavors.

          Voltage: Definition and Measurement

          Voltage, also known as electric potential difference, is a fundamental concept in electrical engineering and physics. It represents the difference in electric potential energy between two points in an electrical circuit. Understanding voltage is crucial for comprehending how electrical systems work and how energy is transferred in circuits.

          At its core, voltage is the driving force that causes electric charges to move through a conductor. It can be likened to the pressure in a water pipe that pushes water through the system. In electrical terms, voltage is the force that pushes electrons through a circuit, enabling the flow of electric current.

          Batteries are common sources of voltage in many electrical devices. A battery creates voltage through a chemical reaction that separates positive and negative charges. This separation of charges establishes an electric field within the battery, creating a potential difference between its terminals. When a circuit is connected to the battery, this potential difference drives the flow of electrons, powering the connected devices.

          As electric current flows through a circuit, it encounters various components such as resistors, capacitors, and inductors. Each of these components causes a voltage drop, which is a reduction in electric potential as charges move through them. This concept of voltage drop is essential for understanding how energy is distributed and used in a circuit. The total voltage provided by the source (like a battery) is divided among the different components in the circuit, with each experiencing a portion of the overall voltage drop.

          The unit of voltage is the volt, named after the Italian physicist Alessandro Volta. One volt is defined as the electric potential difference between two points that will impart one joule of energy per coulomb of charge that passes between those points. This definition highlights the close relationship between voltage, energy, and charge. Essentially, voltage determines how much energy is transferred per unit of charge moving through a circuit.

          The relationship between voltage (V), energy (E), and charge (Q) can be expressed mathematically as V = E / Q. This equation shows that voltage is a measure of energy per unit charge. In practical terms, this means that a higher voltage source can deliver more energy to a circuit for a given amount of charge flow.

          Measuring voltage is a common task in electrical work and is typically done using a voltmeter. A voltmeter is designed to have a very high internal resistance, which allows it to measure voltage without significantly affecting the circuit being measured. To use a voltmeter, it is connected in parallel with the component or section of the circuit where the voltage is to be measured.

          Modern digital multimeters often include voltmeter functionality, making voltage measurement accessible for both professionals and hobbyists. When measuring voltage, it's important to set the meter to the appropriate range and to connect the probes correctly, with the red probe to the positive point and the black probe to the negative or reference point.

          Understanding voltage is crucial for various applications, from designing electronic circuits to troubleshooting electrical systems. It plays a vital role in power distribution, where different voltage levels are used for transmission and household use. In electronics, managing voltage levels is essential for the proper functioning of sensitive components and for ensuring the efficiency and safety of devices.

          In summary, voltage is the electric potential difference that drives current through circuits. It's provided by sources like batteries, experiences drops across circuit components, and is measured in volts. The concept of voltage is intrinsically linked to energy and charge, making it a fundamental parameter in electrical systems. Proper measurement and management of voltage are essential skills in electrical engineering and related fields.

          Kirchhoff's Voltage Law and the Loop Rule

          Kirchhoff's Voltage Law (KVL) is a fundamental principle in electrical engineering that governs the behavior of voltage in closed circuits. This law, also known as the loop rule, states that the sum of all voltage changes around any closed loop in an electrical circuit must equal zero. Understanding and applying KVL is crucial for analyzing complex circuits and solving various electrical problems.

          The loop rule is based on the principle of conservation of energy. In a closed circuit, the energy gained by charges as they pass through sources (such as batteries) must equal the energy lost as they flow through loads (like resistors). This balance ensures that no energy is created or destroyed within the circuit, adhering to the law of conservation of energy.

          To apply the loop rule in voltage analysis, follow these steps:

          1. Choose a closed loop in the circuit.
          2. Select a direction (clockwise or counterclockwise) to traverse the loop.
          3. As you move around the loop, add voltage rises (from negative to positive terminals) and subtract voltage drops (from positive to negative terminals).
          4. Set the sum of these voltage changes equal to zero.

          Let's consider a simple example to illustrate how to apply the loop rule. Imagine a circuit with a 12V battery connected to two resistors in series, R1 (4Ω) and R2 (6Ω). To analyze this circuit using KVL:

          1. Start at any point in the loop (let's choose the negative terminal of the battery).
          2. Move clockwise around the loop.
          3. As we encounter the battery, we add +12V (moving from negative to positive terminal).
          4. Passing through R1, we subtract the voltage drop (I * R1).
          5. Passing through R2, we subtract the voltage drop (I * R2).
          6. Set the equation: 12 - IR1 - IR2 = 0

          This equation demonstrates how the sum of voltage changes around the closed loop equals zero, adhering to Kirchhoff's Voltage Law. By solving this equation, we can determine the current flowing through the circuit and subsequently calculate the voltage drops across each resistor.

          The loop rule becomes particularly useful when analyzing more complex circuits with multiple voltage sources and loads. For instance, in a circuit with two batteries and three resistors forming two loops, we can apply KVL to each loop separately. This creates a system of equations that can be solved simultaneously to find unknown currents or voltages.

          It's important to note that the direction chosen to traverse the loop is arbitrary. Choosing the opposite direction will yield the same results, just with opposite signs. The key is to maintain consistency in the chosen direction throughout the analysis of a particular loop.

          Kirchhoff's Voltage Law also applies to AC (alternating current) circuits, although the analysis becomes more complex due to the time-varying nature of AC voltages. In these cases, complex numbers are often used to represent voltages and currents, but the fundamental principle of KVL remains the same.

          In practical applications, engineers and technicians use KVL to troubleshoot circuits, design power distribution systems, and analyze complex electronic networks. For example, in a multi-cell battery pack, KVL helps ensure proper voltage distribution and balance among individual cells. In power transmission systems, it aids in calculating voltage drops along transmission lines and determining the need for voltage regulators or transformers.

          Understanding and applying Kirchhoff's Voltage Law and the loop rule is essential for anyone working with electrical circuits. It provides a powerful tool for analyzing voltage relationships in closed circuits, from simple battery-powered devices to complex industrial electrical systems. By mastering this fundamental principle, one can gain deeper insights into circuit behavior and develop more efficient and reliable electrical designs.

          Voltage in Series and Parallel Circuits

          Understanding how voltage behaves in series and parallel circuits is fundamental to circuit analysis and electrical engineering. This knowledge is crucial for designing and troubleshooting various electrical systems. Let's explore the concepts of voltage in both series and parallel circuits, including the important principle of voltage division.

          Voltage in Series Circuits

          In a series circuit, components are connected end-to-end, forming a single path for current flow. The key characteristic of voltage in a series circuit is that it divides across the components. This phenomenon is known as voltage division. The total voltage supplied by the source is equal to the sum of the voltage drops across each component in the circuit.

          For example, consider a series circuit with three resistors: R1 = 10Ω, R2 = 20Ω, and R3 = 30Ω, connected to a 12V battery. The voltage across each resistor can be calculated using Ohm's Law and the principle of voltage division:

          • Total resistance: R_total = R1 + R2 + R3 = 60Ω
          • Current: I = V_total / R_total = 12V / 60Ω = 0.2A
          • Voltage across R1: V1 = I * R1 = 0.2A * 10Ω = 2V
          • Voltage across R2: V2 = I * R2 = 0.2A * 20Ω = 4V
          • Voltage across R3: V3 = I * R3 = 0.2A * 30Ω = 6V

          As we can see, the sum of the individual voltage drops (2V + 4V + 6V = 12V) equals the total voltage supplied by the battery, demonstrating voltage division in action.

          Voltage in Parallel Circuits

          In contrast to series circuits, parallel circuits provide multiple paths for current flow. The most important characteristic of voltage in parallel circuits is that it remains constant across all parallel branches. This means that each component in a parallel circuit experiences the same voltage as the source.

          Let's consider a parallel circuit with three resistors: R1 = 10Ω, R2 = 20Ω, and R3 = 30Ω, connected to a 12V battery. In this case:

          • Voltage across R1 = Voltage across R2 = Voltage across R3 = 12V

          While the voltage remains constant, the current through each resistor will vary based on its resistance, following Ohm's Law:

          • Current through R1: I1 = V / R1 = 12V / 10Ω = 1.2A
          • Current through R2: I2 = V / R2 = 12V / 20Ω = 0.6A
          • Current through R3: I3 = V / R3 = 12V / 30Ω = 0.4A

          The total current drawn from the source is the sum of these individual currents: I_total = 1.2A + 0.6A + 0.4A = 2.2A

          Practical Applications

          Understanding voltage behavior in series and parallel circuits has numerous practical applications. In series circuits, voltage division is used in voltage divider circuits, which are essential in many electronic devices for scaling down voltages. For instance, potentiometers use this principle to control volume in audio equipment or brightness in lighting systems.

          Parallel circuits, with their constant voltage characteristic, are commonly used in household electrical systems. This allows

          Practical Applications of Voltage in Everyday Life

          Voltage concepts play a crucial role in our daily lives, with applications ranging from household electrical systems to portable electronic devices. Understanding voltage is not only essential for the proper functioning of these systems but also for ensuring electrical safety and promoting energy efficiency. In this section, we'll explore the real-world applications of voltage and its importance in various aspects of our modern lifestyle.

          One of the most common applications of voltage is in household electrical systems. The standard voltage in residential settings varies by country, typically 120V in North America and 230V in many European countries. This voltage powers everything from lighting fixtures to large appliances like refrigerators and washing machines. The consistent voltage supply ensures that these devices operate efficiently and safely. In some cases, households may have both 120V and 240V circuits to accommodate different appliance requirements.

          Batteries in electronic devices are another prime example of voltage applications in everyday life. From smartphones and laptops to remote controls and portable speakers, these devices rely on batteries that provide a specific voltage to function correctly. For instance, a typical AA battery provides 1.5V, while a smartphone battery might supply 3.7V. The voltage from these batteries is carefully regulated to ensure the device receives the appropriate power without damaging sensitive components.

          Power supplies for various electronic devices also demonstrate the importance of voltage concepts. These units convert the higher AC voltage from wall outlets to the lower DC voltage required by most electronic devices. For example, a laptop charger might convert 120V AC to 19V DC. Understanding voltage is crucial when selecting the correct power supply for a device, as using the wrong voltage can lead to malfunction or damage.

          In the automotive industry, voltage plays a vital role in vehicle electrical systems. Most cars operate on a 12V system, with the battery providing power for starting the engine and running various electrical components. Some hybrid and electric vehicles use higher voltage systems, often 48V or more, to meet the increased power demands of electric drivetrains.

          Renewable energy systems, such as solar panels and wind turbines, also rely heavily on voltage concepts. These systems generate electricity at varying voltages, which must be converted and regulated to match the grid voltage or to charge batteries for off-grid applications. Understanding voltage is crucial for designing efficient and safe renewable energy installations.

          Electrical safety is another area where knowledge of voltage is paramount. High voltage can be extremely dangerous, potentially causing severe injury or death. Electricians and other professionals working with electrical systems must have a thorough understanding of voltage to implement proper safety measures and avoid accidents. Even for the average person, basic voltage awareness can help prevent hazardous situations, such as overloading circuits or mishandling electrical devices.

          Energy efficiency is closely tied to voltage management. Many modern appliances and electronic devices incorporate voltage regulators and power management systems to optimize energy use. For example, variable frequency drives in industrial motors adjust the voltage and frequency to match the load, significantly reducing energy consumption. In homes, LED bulbs and energy-efficient appliances often include circuitry to operate effectively across a range of input voltages, contributing to overall energy savings.

          The telecommunications industry relies heavily on voltage concepts for signal transmission and network infrastructure. From the voltages used in fiber optic systems to the power supplies for cell towers, understanding and managing voltage is crucial for maintaining reliable communication networks.

          In the medical field, voltage plays a vital role in various diagnostic and therapeutic devices. Equipment such as ECG machines, defibrillators, and pacemakers all rely on precise voltage control for their operation. Ensuring the correct voltage in these devices is literally a matter of life and death.

          As we continue to advance technologically, new applications of voltage concepts emerge. The development of smart grids, for instance, involves sophisticated voltage management to balance power distribution and integrate renewable energy sources. In the realm of consumer electronics, wireless charging technologies utilize electromagnetic fields to induce voltage in device batteries without direct electrical contact.

          In conclusion, voltage concepts have far-reaching applications in our daily lives, from powering our homes and devices to ensuring our safety and promoting energy efficiency. As technology continues to evolve, understanding voltage will remain crucial for developing innovative solutions and maintaining the electrical systems that underpin modern society. Whether you're a professional in the electrical field or simply a consumer, having a basic grasp of voltage concepts can lead to safer, more efficient use of electrical energy in all aspects of life.

          Conclusion: Mastering Voltage Concepts

          In this exploration of voltage in electric circuits, we've covered essential concepts that form the foundation of electrical engineering. The introduction video provided a crucial visual understanding of voltage, helping to demystify this fundamental aspect of electricity. Key points include the definition of voltage as electrical pressure, its role in driving current through circuits, and the relationship between voltage, current, and resistance as described by Ohm's Law. Understanding voltage is critical for designing and troubleshooting electrical systems. We encourage you to delve deeper into electrical engineering topics, as this knowledge opens doors to countless practical applications. From household wiring to complex electronic devices, the principles of voltage are at work everywhere. Take this opportunity to apply your newfound knowledge in real-world scenarios. Experiment with simple circuits, measure voltage in everyday devices, or even start a DIY electronics project. The world of electrical engineering awaits your exploration and innovation!

          What Makes Up a Circuit?

          Understanding what makes up an electric circuit is fundamental to grasping the concepts of voltage, current, and resistance. An electric circuit is essentially a closed loop that allows electric charge to flow through it. Let's break down the components and steps involved in creating a basic electric circuit.

          Step 1: Introduction to Electric Circuits

          An electric circuit is a closed loop that electric charge flows within. The term "closed loop" means that the circuit is completely connected with no breaks, allowing the electric charge to flow uninterrupted. The flow of electric charge in a circuit is known as current.

          Step 2: Main Components of a Circuit

          A circuit is not just a simple metal loop; it consists of several key components:

          • Source of Electric Energy: This is typically a battery that provides the necessary energy for the circuit.
          • Connecting Wires: These wires create the closed loop through which the electric charge flows.
          • Devices that Use Electrical Energy: These are the components that consume the energy provided by the source, such as light bulbs or other electronic devices.

          Step 3: Drawing a Schematic Diagram

          To simplify the representation of electric circuits, we use schematic diagrams. These diagrams use standardized symbols to represent the various components of the circuit:

          • Battery: Represented by a longer line (positive terminal) and a shorter line (negative terminal) parallel to each other.
          • Connecting Wires: Represented by straight lines connecting the components.
          • Light Bulb: Represented by a curly Q with a circle around it or a zigzag line (resistor).
          The schematic diagram helps in visualizing and understanding the circuit's structure and function.

          Step 4: Understanding Voltage, Current, and Resistance

          There are three main concepts that are crucial to understanding electric circuits:

          • Voltage: This is the potential difference provided by the battery, driving the flow of electric charge through the circuit.
          • Current: This is the flow of electric charge through the circuit, typically starting from the positive terminal of the battery and moving towards the negative terminal.
          • Resistance: This is a property of the devices in the circuit that use up the electrical energy. It measures how difficult it is for the electric charge to flow through the circuit.

          Step 5: Additional Symbols in Schematic Diagrams

          There are additional symbols used in schematic diagrams to represent other components:

          • Switch: Represented by two dots along a connecting wire, indicating whether the circuit is open (disconnected) or closed (connected).
          • Voltmeter: A device that measures voltage, connected externally to the circuit to measure the potential difference across two points.
          • Ammeter: A device that measures current, connected directly into the circuit to measure the flow of electric charge.

          Step 6: Practical Application

          Understanding these components and how to represent them in schematic diagrams is essential for solving problems related to electric circuits. By knowing how to draw and interpret these diagrams, you can analyze and troubleshoot circuits effectively.

          FAQs

          1. What is voltage and how is it measured?

            Voltage is the electric potential difference between two points in an electrical circuit. It's measured in volts (V) using a voltmeter or multimeter. Voltage represents the force that drives electric current through a circuit and is often described as electrical pressure.

          2. How does voltage behave in series and parallel circuits?

            In series circuits, voltage is divided across components, with the total voltage equal to the sum of individual voltage drops. In parallel circuits, voltage remains constant across all branches, with each component experiencing the same voltage as the source.

          3. What is Kirchhoff's Voltage Law?

            Kirchhoff's Voltage Law (KVL) states that the sum of all voltage changes around any closed loop in an electrical circuit must equal zero. This law is based on the principle of conservation of energy and is crucial for analyzing complex circuits.

          4. How does voltage relate to power in electrical systems?

            Power in electrical systems is calculated by multiplying voltage by current (P = V * I). Higher voltage can deliver more power for a given current, which is why high-voltage transmission lines are used for efficient long-distance power distribution.

          5. What are some common voltage levels in everyday applications?

            Common voltage levels include 1.5V for AA batteries, 3.7V for smartphone batteries, 5V for USB charging, 12V for car electrical systems, and 120V or 230V for household mains power, depending on the country. Understanding these levels is important for safely using and designing electrical devices.

          Prerequisite Topics

          Understanding the concept of voltage is crucial in the field of electrical engineering and physics. However, to fully grasp this fundamental concept, it's essential to have a solid foundation in its prerequisite topics. One of the most important prerequisites for understanding voltage is electric potential and electric potential energy.

          Electric potential and electric potential energy form the basis for comprehending voltage. These concepts are intrinsically linked to the idea of electric potential difference, which is essentially what voltage represents. By delving into these prerequisite topics, students can develop a more comprehensive understanding of how electrical energy is stored and transferred within a system.

          The relationship between electric potential and voltage is particularly significant. Electric potential, often measured in volts, represents the amount of electric potential energy per unit charge at a given point in an electric field. This directly relates to voltage, which is the difference in electric potential between two points in an electrical circuit.

          Understanding electric potential and electric potential energy helps students grasp the concept of work done by electric forces. This knowledge is crucial when studying voltage, as it explains how electrical energy is converted into other forms of energy in various applications.

          Moreover, the prerequisite topic of electric potential difference is essential for comprehending voltage in practical scenarios. It helps explain why electrical current flows from areas of high potential to low potential, which is the fundamental principle behind the operation of electrical circuits and devices.

          By mastering these prerequisite concepts, students can more easily understand complex topics related to voltage, such as Ohm's law, electrical resistance, and power in electrical systems. The knowledge of electric potential and electric potential energy also provides a solid foundation for advanced studies in electromagnetism and electrical engineering.

          In conclusion, a thorough understanding of electric potential and electric potential energy is vital for students aiming to master the concept of voltage. These prerequisite topics not only provide the necessary background knowledge but also help in developing a intuitive grasp of electrical phenomena. By investing time in studying these foundational concepts, students can significantly enhance their understanding of voltage and its applications in various fields of science and technology.

          In this lesson, we will learn:

          • What is an electric circuit and what are the main components: battery (voltage), closed wire path (current), and devices/resistors that use up electricity (resistance)?
          • How to draw a schematic diagram using simplified symbols to represent a circuit.
          • How to tell the difference between series vs. parallel configurations for resistors in a circuit.
          • What is a battery and how does it provide voltage for an electric circuit?
          • What is voltage?
          • Kirchhoff’s 2nd Rule: Loop Rule for solving voltage questions
          • Voltage in parallel rule: the voltage used in parallel settings are EQUAL

          Notes:

          • An electric circuit is a closed loop that electric charge flows within; circuits contain 3 main components:
            • (1) a source of electrical energy (battery)
            • (2) a complete pathway for electric charges to flow through (wire), and
            • (3) one or more devices that use up electricity (electronics, resistors).
          • A schematic diagram is a simplified drawing of an electric circuit which uses universal symbols for each component of an electric circuit. A battery’s (+) positive terminal is drawn as a longer line whereas its (-) negative terminal is drawn as a shorter line.
          • The conventional current is the flow of positive charge, starting from the battery’s (+) positive terminal, travelling through the entire circuit, and ending at the (-) negative terminal.
          • An electric circuit’s attached electronic devices (lightbulbs or resistors) can be connected in either series or parallel configurations.
            • Series: resistors are connected in series if they are in a single and continuous path
            • Parallel: resistors are connected in parallel if they are in multiple, branching paths
          • A battery provides voltage to an electric circuit; it drives the electricity throughout the circuit.
            • A battery converts chemical energy into electrical energy; the reduction-oxidation reaction that occurs within the battery generates excess free energy which is put into the circuit as electrical energy.
          • Voltage is a type of electrical potential difference. The voltage of a battery represents how much energy it can provide the circuit; voltage can also represent how much energy is lost/used across resistors/devices (“voltage drop”).
          • The unit for voltage is Volts (V) (which is equivalent to Joule/Coulomb or energy per charge). It is a scalar quantity.
          • Kirchhoff’s 2nd Rule, also known as the Loop Rule, states that the sum of charges in electric potential (voltage) around the circuit (closed path) will be equal to zero.
            • In other words, all the voltage stored in the battery will be used up by the devices (resistors) in the circuit; the magnitude of battery voltage is equal to the sum of all voltage drops across resistors in the circuit.
          • Voltage in parallel configurations have a special rule: the voltage used in parallel settings are EQUAL (each parallel branch will have the same amount of voltage drop).
          • We will use the stair case analogy for voltage (going down stairs in a building).
            • Starting with the battery voltage (at the positive terminal) as the top floor, and going down a number of floors at each resistor (voltage drop), until you get to floor zero (end at the negative terminal)