Parts of a Circuit: Types & Components in Electric Circuits
- SkillCat Team
- Apr 1
- 21 min read
Updated: 11 minutes ago
Introduction to Electrical Circuits
Electrical circuits power everything you touch—your smartphone, computer, the machinery that builds our world, and every appliance in your home. These circuits are systems that move current through components, making your devices work exactly as they should. Electrical circuits form the backbone of modern technology, powering everything from digital devices to advanced industrial systems. You need to understand how circuits work if you want to troubleshoot problems, design new systems, or simply appreciate the technology that runs your life.
You’ll find circuits categorized by how their components connect and how current moves through them. The core types include series circuits, parallel circuits, open circuits, and closed circuits. Each type performs differently and affects how your entire circuit operates. The components you choose—resistors, switches, power sources—determine exactly how your circuit behaves. The crucial role of electrical circuits in enabling reliable operation and innovation across various industries cannot be overstated. As technology advances, you need this fundamental knowledge more than ever to keep modern devices running safely and efficiently.
Electrical circuits and electronic systems are also essential in the automotive industry, where they contribute to vehicle performance, safety, and comfort.
Electricity Fundamentals: Chapter 2
Power Sources and Current Flow
Every electrical circuit needs a power source to deliver the electrical energy that makes everything work. You’ll work with batteries, generators, and power supplies — each one built to feed energy into your circuit exactly how you need it. The power source creates voltage, and that voltage drives current through every component in your circuit. This voltage is also known as the potential difference, which is measured between two points in the circuit.
Batteries generate electrical energy through chemical reactions that occur within their cells.
Current flows from the positive terminal (in circuit diagrams, the positive terminal is often represented by a long line and the negative terminal by a short line), travels through your components — resistors, switches, loads — and returns to the negative terminal. That completes your loop. You control how current flows by choosing your circuit configuration and components. Build a series circuit, and current passes through each component one by one. Wire it in parallel, and current takes multiple paths through your circuit.
Master how power sources and current flow work together, and you’ll design circuits that work and fix problems fast. Analyze the current flow, understand what each component does, and you’ll build circuits that run safe and efficient every time.
Circuit Diagrams and Design
Circuit diagrams are your roadmap to electrical mastery. These powerful tools use standardized symbols that represent every component you’ll work with — resistors, capacitors, switches, and power sources. Each component in a circuit diagram is represented by a specific circuit symbol, such as the symbol for a battery (constructed by combining multiple cell symbols) or a resistor. You can visualize exactly how any circuit works and spot problems before they happen. Smart technicians rely on these diagrams to understand circuit operation and troubleshoot like pros.
You need to know the characteristics of every component when you design circuits. Resistance, capacitance, and inductance determine how your circuit performs and whether it meets specs. A simple circuit diagram uses basic symbols to represent the same circuit in a clear and understandable way, making it easier to interpret and analyze. When drawing circuit diagrams, it's important to show when wires cross without making electrical contact, to avoid confusion and ensure accurate representation. Circuit diagrams let you communicate complex designs clearly, solve problems fast, and maintain equipment that keeps working. Whether you’re building simple circuits or complex systems, these diagrams give you the foundation to make every component work together perfectly. Different components and circuit configurations have distinct characteristics that influence their representation and function in circuit diagrams.
When discussing capacitors, note that fixed capacitors are represented by two parallel lines in circuit diagrams, and this symbol does not indicate polarity. The two parallel lines in the capacitor symbol represent the plates of the capacitor.
Types of Electric Circuits
This module focuses on identifying the different types of electrical circuits and on applying the formulas covered in the previous unit. We will also introduce new electrical laws to allow for calculation in more complex circuits.
An electrical circuit is a closed path that allows electric current to flow from a power source through various circuit components (such as resistors, switches, and loads) and back again. Each component in a circuit is designed to perform a specific function essential to the circuit’s operation. These fundamental components each play a critical role in ensuring the circuit operates as intended. Circuits are used to power various electrical devices, making them fundamental in many applications. Understanding the parts of a circuit and how current flows through them is essential for technicians.
The three basic types of electrical circuits are: Circuits are made up of various components, each contributing to the overall function and reliability of the system. To learn more about how to measure current using a multimeter, check out this comprehensive guide.
Series circuits
Parallel circuits
Combined (series-parallel) circuits
We also use circuit diagrams to show these circuits with standard circuit symbols for each component.
Series Circuits
A series circuit is any circuit where the electric current has only one path to follow. In a series circuit, components are connected end to end, forming a single path for current to flow through all of them in a continuous sequence. A series circuit can have multiple power sources, loads, and other components, but there is still only one continuous electrical path.
For series circuits, current must pass through every part of the circuit before returning to its source. If the series circuit is open at any point, current stops flowing and all components stop working. This could be because a switch is open, as shown in this image, or because a component failed.
A common example of a series circuit is the light switch and light bulb on your wall. The switch is in series with the light bulb
When the switch is closed, current flows from the power source through the switch, through the light bulb, and back to the source, producing light energy. When the switch is opened, the circuit is open and no current flows.
Fuses are another example of a series circuit. Fuses are designed to protect electrical devices and equipment sensitive to overload by stopping the flow of current if it exceeds the rated amount. If more current flows through a fuse than it is rated for, it will burn open (also called breaking), creating an open circuit and protecting the rest of the system.
The circuits in many electrical and electronic devices require very precise voltages and currents to work properly. Knowing some of these values means we can calculate the others. For this, we can use Ohm’s law, which states that V=I*R, as discussed earlier, as well as new laws for circuits.
In order to better understand how to solve for variables in electronic circuits, we must first understand Kirchhoff’s Circuit Laws. Kirchhoff established the following 2 fundamental laws for understanding circuits.
Kirchhoff’s Current Law
Kirchhoff’s Voltage Law
Kirchhoff’s Current Law states: “The algebraic sum of currents in a network of conductors meeting at a point is zero.” In other words, the current entering any junction (node) equals the current leaving that junction.
Kirchhoff’s Voltage Law states: The directed sum of the potential differences (voltages) around any closed loop is zero. In other words, if we trace the path of electricity around a closed circuit, the sum of all voltage rises and drops is zero. Voltage sources add energy to the circuit; loads such as resistors remove (drop) that energy.
We know that the current entering any junction, or node, is equal to the current leaving that junction. Series circuits only have one path for current to flow, meaning that for any given point in a circuit, the current in equals the current out. In a series circuit, the current is the same at all points in the circuit.
In the example to the right, the current flowing through each voltage source and each resistor is the same and is also equal to the total current for the circuit.
ITotal = IVS1 = IVS2 = IR1 = IR2 = IR3
In any circuit, if we trace the path of electricity back to its origin, the total voltage is equal to zero. For a series circuit, there is only one path for electricity to travel, so the sum of all voltage changes in the loop adds to zero.
Voltage sources facing the same direction add together to increase voltage. Voltage sources facing opposite directions subtract. Resistances cannot increase voltage in any direction, they only subtract. So for our example:
VTotal = VVS1 + VVS2 - VR1 - VR2 - VR3 = 0
It is also useful to know that all resistances in a series circuit, can be simplified to represent a single resistance for that circuit. In other words, the total resistance of a circuit is the sum of all resistances in the circuit.
In the example to the right, the total resistance for the circuit is equal to the sum of all 3 resistances.
RTotal= R1+ R2+ R3
If each resistor has a resistance of 2Ω, the total resistance of the circuit is 6Ω.
RTotal= 2Ω + 2Ω + 2Ω = 6Ω
Each resistor has a specific resistance value that determines how much it opposes current flow. Electrical resistance is the property that determines how much a component opposes the flow of electric current in a circuit. This basic component rule for series circuits is one of the fundamental building blocks of circuit analysis.
Parallel Circuits
Parallel circuits are any circuit where current has more than one path to follow. Parallel circuits allow multiple components to be connected across common points, creating separate pathways for current. Even if one branch of the circuit is open, electric current may still be able to flow through the other branches of the circuit.
One common example of a parallel circuit is the wiring in our homes. If a breaker trips in your kitchen, it usually does not turn off all electrical devices. Generally it only affects a few of the appliances in your kitchen.
In a parallel circuit, the total current for the circuit equals the sum of currents in each parallel branch. In the example to the right, the total current from the batteries equals the sum of current flowing through each resistor.
ITotal = IR1 + IR2 + IR3
When multiple resistors are added in parallel, they decrease the overall circuit resistance. The total resistance in a parallel circuit will always be less than the resistance in any one branch.
1/RTotal = 1/R1 + 1/R2 + 1/R3
In a parallel circuit, voltage is equal in each branch. In the example to the right, if the two batteries produce a total voltage of 12V, then that is how much flows through each parallel branch and also through each resistor.
VTotal = VR1 + VR2 + VR3
Combined Circuits
In a combined or series-parallel circuit, there are elements of both series and parallel circuits. The rules that apply for either series or parallel circuits cannot be applied directly for combined circuits. Instead, the circuits need to be simplified into series and parallel parts. Then the rules can be applied.
Most circuits are combined circuits. Turning off the light in your bathroom may turn off the outlet for a curling iron, but it won't turn off your refrigerator. Also, your home's electrical panel can be used to shut off power to parts of your home, without affecting the whole house.
A switch can be used to open the circuit and prevent current flowing through R3. However, current will keep flowing through both R1 and R2 after the switch is opened.
We can visualize combined circuits as a combination of series and parallel circuit rules. In the example to the right, R1 and R2 are in series, as are R1 and R3. These resistances can be added because of series circuit rules. R2 and R3 are parallel instead, so they must use parallel circuit rules.
There are three main types of circuits: series, parallel, and combined circuits. Using values that can be obtained through measurement together with Kirchhoff's Circuit Laws and Ohm's Law, we can solve for almost any missing values.
Open and Closed Circuits
Every electrical circuit works on one simple rule: it’s either open or closed. You get an open circuit when something breaks the path — a disconnected wire, an open switch, or any interruption that stops current dead in its tracks. No current flows. Your electrical devices won’t work. Period. Open circuits happen when you flip a switch off or when connections break down over time.
A closed circuit gives you exactly what you need: a complete path that lets current flow from your power source, through every component, and back home. However, a short circuit can occur when a low-resistance path bypasses the intended circuit elements, causing excessive current flow. Such conditions can result in component damage, so it’s essential to include protective devices in circuit design. Close that circuit, and your electrical devices fire up like they’re supposed to. You want to troubleshoot electrical problems fast? Master the difference between open and closed circuits first. This knowledge separates real electricians from guesswork. When devices won’t start, check for open circuits before you waste time on complex diagnostics. Switches put you in control — they open and close your circuits safely, giving you complete command over electrical flow.
Switches and Loads
This module introduces the basics of electric switches, as well as some of the most common switches. It also defines loads and introduces some of the more common electric loads. Skip to quiz!
Switches
Switches are devices that can open or close an electric circuit, and can be activated at will. Recall that a closed circuit is one where electric current can flow, forming a closed-loop. An open circuit is one where no current can flow.
Given the wide variety of uses that switches can have, there are many ways of classifying them. Two of the most common ways to classify switches are by:
Contacts, or by
Actuators
Describing a switch by its contacts means describing it by how it can be used in a circuit.
Describing a switch by its actuator means describing how the switch is mechanically activated. For example, the switch shown has a toggle actuator and only two contacts.
Switches have conductive pieces called contacts, which connect to the external electrical circuit. Normally open switches have contacts that ‘close' when activated. Normally closed switches have contacts that ‘open' when activated.
The variation on number of contacts and possible positions a switch can have are used to describe switch variations. The term ‘pole' is used to describe the number of contacts a single switch has. ‘Throw' is the term given to the amount of operating positions of a switch
An SPST switch has only one set of terminals that can be open or closed. An example of this type of switch is a regular light switch, with off/on positions.
A DPST switch has two sets of terminals that are opened or closed by the same mechanism. This is analogous to having two SPST switches controlled by one single mechanism.
An SPDT switch has three contacts, a single input and two outputs. This means that the input can be connected to either of the outputs, but not to both at the same time. One of the outputs will be normally closed, and the other will be normally open.
A DPDT switch has six contacts, two inputs and four outputs. This is analogous to having two SPDT switches controlled by a single mechanism.
Another way to classify switches is by means of their actuator. The actuator is the moving part that applies the force that makes the contacts change position. They can be easily distinguished by how a person activates the switch.
A simple switch that is normally open, and closes the circuit after being pressed. These switches are generally used for ON/OFF functions, or to send signals.
A thermostat is a device that combines a switch and a temperature sensor. The switch opens and closes the heating or cooling circuit, and the sensor tells it when to do so. In this case, a person is not required to provide physical force to activate the switch.
A pressure switch activates an electrical switch when a pre-established fluid pressure is achieved. They are often found in HVAC systems, as part of the operation or safety controls.
Another switch that includes a sensor, flow switches are used to control the flow of liquid and gas through a channel. They activate if the flow of liquid or gas gets either too high or too low.
Loads
Recall that the loads in a circuit are the devices that consume power. They are the reason a circuit is created, since providing them electric power is the objective of an electrical circuit. They take electric power and transform it to another form of useful energy, such as heat, movement, or light. If you want to learn more about checking the condition of these loads, see this guide on how to measure resistance with a multimeter.
Loads can be resistive, capacitive, or inductive in nature. They can also be a combination of those three. It is important to understand the size and type of load that will be connected to an electric circuit.
Electric heaters are devices that take advantage of the ability of resistors of heating up. By running a high current through a heating element (resistor) they transform electricity into heat. The most common metal used as the heating element is called nichrome. Variable resistors, such as potentiometers, are a type of resistor that allows for adjustable resistance in circuits, providing variable control in electronic applications.
Inductive loads are devices made up of inductors. These devices take advantage of the magnetic field created by the inductors to perform a task. Electric motors and transformers are examples of inductive loads.
Capacitive loads use capacitors, which store and release electrical energy in the electric field between their plates. Capacitors store energy electrostatically, allowing them to smooth voltage fluctuations, filter signals, and serve in timing applications. Unlike rechargeable batteries, capacitors can charge and discharge rapidly, making them ideal for these circuit functions.
The term solenoid is used for a coil of wire (inductor) when it is used as an electromagnet. This means converting electrical energy, to magnetic, to mechanical. They are commonly used in mechanical switches, valves, and as the starters on automobiles.
Some loads, especially in telecommunications, are specifically designed for signal processing. These loads manage high-frequency signals, handle data encoding, and ensure accurate and efficient data transmission.
These are lights used to convey messages in displays, and consume very little power. HVAC systems sometimes have them in the control boards to indicate status or troubleshooting codes. These lights come in different colors to transmit a wide variety of messages.
Knowing and understanding how different switches and loads operate is essential to creating and using circuits properly. Switches come in many forms and are very versatile. Loads have three basic components, but can be combined to create a wide array of circuits.
Circuit Components
This module will introduce common circuit components used in electrical installations. These components include relays, contactors, transformers, motors, and circuit protection devices.
Controllers
Operations such as the closing or opening of switches or contacts are carried out by magnetic controllers. A magnetic controller will automatically perform all intended operations in the proper sequence after the closure of a switch.
Relays
Recall that switches are devices that can connect and disconnect circuits, activated by physical force. If the switch is operated electrically, and not manually, the device is called a relay.
When the first circuit is closed, an electric current flows through the coil in the relay. This coil
creates a magnetic field that attracts or repels the moving portion of the relay. This closes the secondary circuit, which powers the load to which the relay is connected.
As with switches, there are many types of relays that accommodate different purposes. Control relays operate control circuits and light duty loads, or even control the coil of another relay in the case of pilot duty control relays. Fan duty or service duty relays are mostly used to control fan motors.
Relays have throws and poles, just like switches. Recall that ‘pole' refers to the number of contacts, and ‘throw' to the number of operating positions. This means relays are also classified as SPST, SPDT, DPST, DPDT, and so on.
The control side of a relay has a voltage rating required to trigger the switch. The contacts side of a relay has a rating for both voltage and current, and should be operated within this rating.
Contactors
Like relays, contactors are electrically control switches to open and close circuits. Unlike relays, they are designed for high current applications, such as above 15 amps.
Recall that normally open switches are those whose contacts are open until they are activated. The contacts on a normally closed switch are closed until activated. Contactors are almost exclusively built to be normally open.
Just as switches and relays, contactors can have different amounts of poles, and one or two throws. Throws are limited to two since there are only two positions available for the mobile part.
Just as with relays, contactors have a voltage rating for their control circuit and a current and voltage rating for the contacts. There are three current ratings:
Resistive rating,
Full load amps (FLA) rating, and
Locked rotor amps (LRA).
Transformers
Transformers are used to transfer electrical power from one circuit to another. The two circuits are not physically connected with wires. They are commonly seen mounted on poles along distribution lines.
Transformers work by using the properties of inductors. Recall inductors create a magnetic
field around them, and that field can induce a voltage in conductors inside them. Transformers have, at minimum, one pair of physically isolated inductors.
The main purpose of a transformer is to transfer electrical energy between two circuits while changing the voltage value. Transformers are highly efficient, so the power transferred between circuits remains essentially the same. This means the amount of current in the secondary circuit changes depending on the voltage change.
Transformers can only work if using alternating current (AC), and not with direct current (DC). Recall that in AC current flows in both directions, while in DC current flows in only one direction. Diodes are commonly used for converting AC to DC through a process called rectification, which is essential in many electronic devices.
The two circuits connected to the coils in transformers are named primary and secondary circuits. If the voltage in the secondary circuit is bigger than the voltage in the primary, the transformer is a step-up transformer.
If the voltage in the secondary circuit is smaller than the voltage in the primary, the transformer is a step-down transformer. The number of turns each of the coils have determines the change in voltage between primary and secondary windings.
Multi-tap transformers have several taps on either primary or secondary windings. By choosing different taps, the transformer can be step-up or step-down, providing options according to changing needs.
The high side of a transformer is the one that has the high-voltage and low-current. The low side of a transformer is the one that has the low-voltage and high-current.
Motors
Electrical motors use electrical energy to create mechanical rotational. The attracting and repelling forces of magnets and electromagnets inside the motor cause it to spin.
There is a very wide variety of electric motors, that cover many different needs. One of the most popular types of motors is the induction motor. Induction motors use the property of induction of current to create a rotational movement.
There are different approaches to get an induction motor to start turning.
A split-phase motor utilizes an extra small winding to provide the initial rotation direction to the motor. A permanent split capacitor (PSC) motor uses a permanently connected capacitor to correctly start.
Electronically commutated (EC) motors are a type of permanent magnet motor that is highly efficient and controllable. The control of the motor is provided by electronic components, making it very accurate and versatile.
Circuit Protection Devices
Sometimes electrical circuits can experience excessive amounts of current caused by overloads or short circuits. These currents can damage the electrical equipment, which is why
there are devices to protect them in these cases.
One of the most basic devices for protection, disconnectors are used to ensure that an electrical circuit is completely de-energized. Usually manually controlled by a lever or switch, they physically open the circuit to prevent current flow.
Fuses are devices that burn up if too much current flows through them, opening the circuit and avoiding damage. Circuit breakers can also open a circuit if too much current flows through them. Fuses are a one-time use, while circuit breakers can be reset.
Circuit components come in many different varieties, accomplishing many varied objectives. Most of them are loads, but there are also controllers and protective equipment. They have to be well understood before any attempt to use them.
Electrical Circuit Safety Precautions
You know electrical circuits demand respect — and smart electricians never cut corners on safety. Turn off that power source before you touch anything. De-energize the circuit completely. Gear up with insulated gloves and safety glasses. These aren't suggestions — they're your professional armor against electrical shock and injury.
Verify every component matches your circuit's voltage and current ratings. Mismatched parts overheat and fail. Install fuses and circuit breakers that automatically cut excessive current flow. These safety features protect your circuit and connected equipment. Follow these fundamentals, and you'll work safely while building the reputation that gets you hired and keeps you working.
Circuit Representation
You need to know how to represent electrical circuits — it's non-negotiable if you're serious about working with electrical devices or systems. Circuit representation uses visual tools, and circuit diagrams are your go-to method. These diagrams show you exactly how components connect and how current flows. You'll see standardized symbols for resistors, switches, power sources, and every other component. One glance tells you how the whole system operates.
Think of circuit diagrams as your blueprint. You build with them. You analyze with them. You troubleshoot with them. Each component and connection gets laid out so you can trace the current's path and understand how every part works together. When you're dealing with complex circuits — multiple components, multiple connections — this visual roadmap keeps you on track.
Here's what separates good technicians and engineers from the rest: they use circuit diagrams to design electrical devices the right way. Every component gets placed correctly. Every connection gets made properly. You spot problems before you start building, which saves time and prevents expensive mistakes. When maintenance or repairs hit your desk, a solid circuit diagram lets you trace faults fast, swap out bad components, and get systems running again.
Circuit representation isn't optional in modern electronics — it's essential. Whether you're building simple circuits or maintaining advanced electrical systems, circuit diagrams ensure every component works together safely and efficiently. Master this skill, and you'll handle any electrical challenge that comes your way.
Question #1: Which type of switch is activated by one mechanism, but opens or closes two sets of contacts?
SPST
DPST
SPDT
DPDT
Scroll down for the answer...
Answer: DPST
Double pole, single throw (DPST) switches have two sets of contacts that open or close simultaneously, by the same mechanism.
Question #2: Which of these devices has a switch that is activated depending on temperature?
Push-button
Flow switch
Pressure switch
Thermostat
Scroll down for the answer...
Answer: Thermostat
Thermostats react to temperature by opening or closing an electrical circuit.
Question #3: Which of these would qualify as an electric load?
A resistor
An inductor and a resistor
A capacitor and an inductor
All of the above
Scroll down for the answer...
Answer: All of the above
Any combination of resistors, inductors, and capacitors are electric loads.
Question #4: What do solenoids use to create a mechanical force?
Magnetic field
Electric field
Heat
Resistance
Scroll down for the answer...
Answer: Magnetic field
Solenoids create mechanical force from the magnetic field created by the inductor.
Question #5: If a series circuit is open because of a gap in the electrical path, current will stop flowing.
True
False
Scroll down for the answer...
Answer: True
True. If the circuit is open in a series-type circuit, current will not flow.
Question #6: Which of Kirchhoff’s Laws tells us that the sum of all voltages in a closed loop is equal to zero?
Kirchhoff’s Current Law
Kirchhoff’s Voltage Law
Kirchhoff’s Law of Electricity
Kirchhoff’s Capacitance Law
Scroll down for the answer...
Answer: Kirchhoff’s Voltage Law
Kirchhoff’s Voltage Law is that the sum of all voltages in a closed loop is equal to zero.
Question #7: If two batteries in series produce 3A of current, how much current passes through the 3 resistors in the circuit shown?
0A
0.3A
1A
3A
Scroll down for the answer...
Answer: 3A
In a series circuit, if ITotal = 3A, then IVS1, IVS2, IR1, IR2, and IR3 also equal 3A each.
Question #8: If two batteries in series produce 12V, and resistors R1 and R2 each cause a voltage drop of 5V, what is the voltage drop across resistor R3?
0V
2V
5V
12V
Scroll down for the answer...
Answer: 2V
0 = 12V-5V-5V-R3
R3=2V
Remember that the voltage in a series circuit must sum to zero.
Question #9: If only one branch of a parallel circuit is open, but another branch is closed, current will stop flowing for the entire circuit.
True
False
Scroll down for the answer...
Answer: False
False. As long as there is one closed path for current to flow from the battery, through the circuit, and back to the battery, some electrical current will flow.
Question #10: If an electrical circuit has 3 resistors in parallel with resistances of 6Ω each, and a total voltage of 3V produced by the two batteries, what is the total current for the circuit?
0.5A
1A
1.5A
6A
Scroll down for the answer...
Answer: 1.5A
1/RTotal = 1/6 + 1/6 +1/6 =0.5Ω +1/Ω
RTotal = 2Ω
ITotal = VTotal/RTotal = 3/2 = 1.5A
Question #11: If we have found a voltage drop across R1 as 7V and across R2 as 1V, what is the voltage drop across R3?
0V
1V
6V
7V
Scroll down for the answer...
Answer: 0V
VR3=0V
As the switch is open, current travels through R2 instead of R3.
No current = no voltage drop.
Question #12: In the diagram, if the switch is closed and we have a voltage drop across R1 as 7V and across R3 as 1V, what is the voltage across R2?
0V
1V
6V
7V
Scroll down for the answer...
Answer: 1V
For parallel circuits, we know that the voltage through each branch must be the same, so VR2=VR3=1V
Question #13: How are relays different from a regular switch?
They can stand higher voltage
They are electrically activated
They look better in an installation
They have a better rating
Scroll down for the answer...
Answer: They are electrically activated
Relays are electrically activated, instead of manually activated.
Question #13: Which of the following is a type of current rating for a contactor?
Locked Rotor Amps (LRA)
Full Load Amps (FLA)
Resistive Rating
All of the above
Scroll down for the answer...
Answer: All of the above
Fahrenheit is the unit of measurement for temperature in the imperial system.
Question #14: What property of a conductor carrying a current allows transformers to work?
Resistance
Hardness
Inductance
Capacitance
Scroll down for the answer...
Answer: Inductance
Transformers work because of the principle of induction.
Question #15: If the voltage in the secondary winding of a transformer is bigger than the voltage in the primary, the transformer is a ______ transformer.
Broken
Step-up
Step-down
Moving
Scroll down for the answer...
Answer: Step-up
A step-up transformer increases the voltage present in the primary winding.
Question #16: Which of these motors is the most controllable?
Induction motor
EC motor
PSC motor
Split-phase motor
Scroll down for the answer...
Answer: EC motor
EC motors are controlled by electronics, making them more controllable than the others.
Question #17: What activates fuses and circuit breakers?
Excessive voltage
Not enough voltage
Excessive current
Not enough current
Scroll down for the answer...
Answer: Excessive current
An excess of current running through a circuit activates the protection offered by fuses and circuit breakers.
Other References:
