EVERYTHING you need to know about about robot power

Summary

In this video, the host covers essential concepts related to power in building robots, explaining key electrical terms like voltage, current, and power. They discuss how to plan and design the power circuit for an autonomous mobile robot, including choosing the right components like motors, batteries, and regulators. The video highlights important safety considerations, including the use of proper wiring, connectors, fuses, and regulators to prevent overheating or short circuits. The next video will show the practical steps of wiring the circuit. Viewers are encouraged to subscribe for future content.

Takeaways

• 🔋 The video is about power management in building robots, focusing on concepts applicable to electronics in general.
• 💡 Key terms to understand: Voltage (measured in volts), Current (measured in amps), and Power (measured in watts).
• 🔧 Power equals voltage times current (P = VI), and adjustments to either voltage or current affect power consumption.
• 🔌 Voltage is usually constant, and current fluctuates based on load; USB devices, for example, always operate at 5V but use varying current.
• 🔥 Devices have maximum current or power ratings, which are critical to avoid overheating or damaging components.
• ⚙️ Robots often need two different voltages: 5V for microcontrollers and USB devices, and higher voltages for motors (e.g., 12V).
• 🔋 Regulators are used to convert higher input voltages to the required voltage, with switching regulators being more efficient than linear ones.
• ⚡ Calculating the current draw for each component helps design a safe and functional circuit, ensuring regulators can handle the load.
• 🔋 Lipo batteries are commonly used in robots, and selecting one with proper voltage, capacity, and discharge rating (C rating) is crucial for performance and safety.
• 🔑 Safety measures include using proper wiring, connectors, a power switch, and a fuse to protect against short circuits and prevent fire hazards.

Q & A

What are the three main electrical terms discussed in the video, and how are they defined?

The three main electrical terms discussed are voltage, current, and power. Voltage (measured in volts) is the potential difference or 'pressure' that pushes electric current through a circuit. Current (measured in amperes or amps) is the flow of electricity through a conductor. Power (measured in watts) is the product of voltage and current, showing how much energy is being used or transferred.

How is power calculated in an electrical circuit?

Power is calculated by multiplying voltage and current, expressed as the equation P = V * I, where P represents power, V represents voltage, and I represents current.

Why are regulators important when designing circuits for robots, and what types of regulators are available?

Regulators are important because they ensure a stable and precise voltage for components, even when the input voltage fluctuates. The two main types of regulators are linear regulators, which are simple but inefficient, and switching regulators, which are more efficient and recommended when handling high currents.

What is the difference between linear regulators and switching regulators?

Linear regulators are simpler and cheaper but are inefficient, especially with high input voltage and large current. Switching regulators (also called switch mode power supplies or buck converters) are more efficient and suitable for situations where higher current is drawn.

Why is it important to choose the correct voltage for motors in a robot, and what should be considered?

Choosing the correct voltage for motors is important because motors have rated voltage levels they work best at. Motors can tolerate slightly higher or lower voltages, but exceeding the motor's rating can damage it. A safe bet for many robots is 12 volts, but checking the motor specifications is essential.

What is the significance of the current rating for both power supplies and components?

The current rating for a power supply indicates the maximum amount of current it can safely provide, while a component’s current rating shows the maximum current it will draw. It’s important to match these ratings to avoid overheating or damaging components.

What is the stall current for motors, and why should it be avoided?

The stall current is the maximum current a motor draws when its output shaft is held still. Running a motor at stall current for more than a brief moment can damage it, so designers should avoid operating the motor near this current.

What factors should be considered when choosing a battery for a robot?

When choosing a battery, consider the voltage, current requirements, and capacity. The battery must supply the required voltage and enough current to run the motors and components. Additionally, the capacity, measured in milliamp-hours (mAh), determines how long the battery will last.

What is the C-rating of a LiPo battery, and how does it affect current draw?

The C-rating of a LiPo battery represents the maximum current that can be safely drawn from it. To calculate this, multiply the battery’s capacity by the C-rating. For example, a 3000 mAh battery with a 20C rating can supply up to 60 amps.

Why are fuses important in a robot’s electrical circuit, and what do they protect against?

Fuses are important for protecting the wiring and battery from short circuits. If a short circuit occurs, the fuse burns out, stopping the flow of current and preventing damage to the wiring and battery. Fuses are essential for safety in electrical systems.

Outlines

00:00

🤖 Introduction to Power for Building Robots

This paragraph introduces the video, focusing on the importance of understanding power in building robots. The video is part of a larger series on building autonomous mobile robots, and it aims to provide fundamental knowledge of voltage, current, and power. The speaker mentions the plan to start by designing a circuit on paper and continue with more detailed discussions in upcoming videos, encouraging viewers to subscribe.

05:02

🔋 Key Concepts: Voltage, Current, and Power

The speaker introduces key electrical concepts essential for understanding power: voltage, current, and power. Voltage is the potential difference (measured in volts), current is the flow of electricity (measured in amps), and power is the product of voltage and current (measured in watts). These principles are crucial for understanding how electricity works in circuits, and the speaker uses the analogy of water pipes to simplify the explanation. Additionally, they emphasize that power equals voltage times current, highlighting the relationship between these terms in various applications.

10:02

⚡ Practical Example of Voltage in Robots

The discussion shifts to applying voltage principles in a robot, particularly the use of 5 volts for microcontrollers like Raspberry Pi and Arduino. The speaker explains that 5-volt batteries don't exist and suggests using a regulator to convert higher voltages to a precise 5V. Two types of regulators are introduced: linear (less efficient) and switching regulators (recommended for their efficiency). The paragraph concludes by addressing the importance of choosing components with appropriate power ratings to avoid overheating or fire hazards.

15:02

🔌 Choosing the Right Voltage and Current for Your Robot

This section explains how to decide on supply voltage based on the robot’s components, such as motors that typically require 12V. Current draw is a critical factor in determining the design, and the speaker shares tips on estimating current usage for different robot components. They recommend being careful and ensuring that the regulator can handle the required power, particularly focusing on the 5V components and their current requirements.

🚀 Motors and Their Power Requirements

The speaker focuses on the current requirements of motors, emphasizing the need to understand stall current, which is the maximum current a motor draws when it stops moving. They explain that exceeding this can damage the motor and suggest reviewing the motor’s datasheet for details. For this robot, two DC motors will be used, and the speaker calculates the total current draw from the 12V power supply.

🔋 Choosing the Right Battery

The speaker provides a detailed explanation of selecting a suitable battery for the robot, recommending LiPo batteries due to their compact size and power. They discuss important battery characteristics like the S number (cell count), voltage, capacity (milliamp-hours), and discharge rating (C number). Safety precautions when working with LiPo batteries are emphasized, including proper charging and avoiding over-discharging.

🔧 Powering Components for Testing

During testing, using a mains-powered power supply instead of a battery is suggested to avoid frequent charging. The speaker describes various power supply options, from a professional bench power supply to makeshift options like using a car battery. The focus is on ensuring the supply provides the correct voltage and current.

🛠️ Wiring, Connectors, and Safety

Wiring and connectors are critical components for safety. The speaker advises using wiring rated for the appropriate current and connectors designed to handle the load. They mention specific connector ratings and caution against using breadboards or jumper wires for high-current applications. An external USB hub is recommended for the Raspberry Pi to handle additional power requirements safely.

🔌 Adding a Power Switch and Fuse

A power switch is recommended to safely turn off the robot and disconnect the battery. The speaker also stresses the importance of adding a fuse to prevent damage from short circuits, explaining how fuses act as a safety measure by breaking the circuit if the current exceeds a safe level. This section emphasizes circuit protection to avoid hazards like wiring damage or battery fires.

📋 Conclusion and Next Steps

The final paragraph wraps up the theory portion of the video. The speaker hints at the upcoming video where the robot will be wired, components examined in detail, and safety measures ensured. They invite viewers to subscribe and leave comments, particularly about safety issues, and encourage feedback for improving future content.

Keywords

💡Voltage

Voltage, often referred to as potential difference, is the amount of electric potential energy between two points in a circuit. In the video, it is described as one of the core concepts to understand about power in robotics. The analogy of voltage being like pressure in a pressurized water tank is used to explain how it drives current through wires, similar to how pressure forces water through pipes. Voltage is measured in volts, and in the context of robots, it's important to select the right voltage for components like microcontrollers and motors.

💡Current

Current, also called amperage, is the flow of electric charge through a circuit, measured in amperes or amps. In the video, it is emphasized that current fluctuates based on the load, meaning different components in a robot will draw varying amounts of current. The relationship between voltage and current is crucial because together they determine the amount of power a device consumes or produces. Components like motors and cameras often require specific amounts of current to function effectively.

💡Power

Power is the rate at which energy is used or transferred in a system, measured in watts. The video explains that power is calculated using the formula P = VI, where power equals voltage multiplied by current. Power ratings are important when choosing batteries, components, and connectors for robots, as exceeding these ratings can lead to overheating, equipment damage, or fire hazards. The presenter emphasizes that ensuring the correct power supply is key to building a safe and efficient robot.

💡Regulator

A regulator is a component that converts a fluctuating input voltage into a stable output voltage, often essential for precise electronic components like microcontrollers. In the video, two types of regulators are mentioned: linear regulators, which are simple and cheap but inefficient, and switching regulators, which are more efficient and preferred for robotics projects. The regulator ensures that components like the Raspberry Pi receive a consistent 5 volts despite the variability in battery output.

💡Stall Current

Stall current refers to the maximum current a motor can draw when it is not able to rotate, such as when its output shaft is forcibly held in place. In the video, the presenter warns against allowing motors to operate near their stall current for prolonged periods, as it can damage the motor. Understanding a motor's stall current is important when choosing appropriate drivers and power supplies for robots, particularly those with heavy loads or high torque requirements.

💡Battery

A battery is a device that stores and provides electrical energy to power a circuit. In robotics, selecting the correct battery is crucial for supplying the right voltage and current to components. The video discusses LiPo (lithium polymer) batteries, commonly used in robotics due to their high energy density and current output. However, the presenter highlights the safety risks associated with LiPo batteries, such as over-discharge and short circuits, which can lead to fires if not handled properly.

💡Linear Regulator

A linear regulator is a type of voltage regulator that uses resistive components to convert higher input voltages to a lower, stable output voltage. While they are simple and inexpensive, they are inefficient when used in circuits that require high current, as they waste energy as heat. The video contrasts linear regulators with switching regulators, explaining that linear regulators are typically included on microcontroller boards like Arduino, but are not suitable for powering high-current robotics systems.

💡Switching Regulator

A switching regulator, also called a switch-mode power supply or buck converter, is a more efficient type of voltage regulator that converts input voltage to a desired output voltage with minimal energy loss. The video suggests using a switching regulator for robotics projects because it efficiently handles higher input voltages and current loads without generating excessive heat. This type of regulator is particularly useful when powering components like motors or microcontrollers that require stable voltages.

💡Fuse

A fuse is a safety device that protects electrical circuits from excessive current by breaking the connection if the current surpasses a certain threshold. The video highlights the importance of including a fuse in robotic circuits to prevent short circuits and overheating. Fuses act as deliberate failure points that sacrifice themselves to protect more expensive components, ensuring that a surge in current doesn't damage wiring or cause a fire.

💡Motor Driver

A motor driver is a component that controls the current sent to motors, allowing them to operate within safe current and voltage ranges. In the video, the presenter explains that motor drivers are essential for managing the current draw of motors, especially in robotics applications where motors can draw large amounts of current under heavy loads. The motor driver ensures that the motor receives the appropriate current without overloading the power supply or the motor itself.

Highlights

Introduction to power concepts for building robots and other electronics, focusing on the principles applicable to autonomous mobile robots.

Explanation of key electrical terms: voltage, current, and power, along with their units of measurement (volts, amps, and watts).

Analogy of voltage as pressure in a water tank, illustrating how voltage drives current through a circuit, with resistance affecting the flow.

Formula: Power equals voltage times current (P = VI). More voltage or current results in more power, and vice versa.

Emphasis on choosing components that match the power supply rating to avoid overheating or potential fire hazards.

Explanation of how voltage regulators work, converting a higher input voltage into a stable lower output voltage for microcontrollers and USB devices.

Comparison between linear regulators and switching regulators, with a recommendation for switching regulators due to their efficiency.

Overview of 12V motors, discussing how they can tolerate over- or under-voltage, and the importance of checking motor specifications.

Calculating current requirements for 5V components in the robot, estimating 5A total draw and ensuring the regulator can handle the load.

Discussion on motor current draw, focusing on stall current (maximum current a motor can draw) and how it affects motor performance and safety.

Choosing the right battery: Introduction to LiPo batteries, including key specifications such as voltage, capacity, and discharge rating.

Safety warnings about LiPo batteries, including proper charging, handling, and storage practices to avoid hazards.

The significance of the C rating in LiPo batteries, which indicates the maximum current the battery can safely supply.

Recommendation for using a mains-powered power supply during bench testing to avoid constant recharging of batteries.

Importance of using appropriate wiring, connectors, and fuses to ensure safe operation and to prevent short circuits or fires.

Transcripts

hey everyone today we're going to be

chatting about power i want to try and

cover everything that you would need to

know when it comes to the topic of power

for building robots now the principles

in this video will apply to all

different kinds of robots in fact all

different kinds of electronics really

but since this is also part of a bigger

series where we're going through how to

build an autonomous mobile robot from

start to finish i'll be using that in

all the examples throughout if that

project sounds interesting to you check

out the description i'll include a link

to the full playlist so you can watch

that later today we're going to be

planning out the circuit on paper making

sure we understand everything and then

in the next video i'll be wiring up the

circuit and we'll be able to go through

a bunch of the components in more detail

make sure you subscribe so that you

don't miss out on that

let's start by reviewing some of the key

concepts to understand about power

when we're talking about electricity and

kind of how much of it there is there

are three terms we'll usually come

across firstly there's voltage sometimes

called potential difference and that's

measured in volts

then we've got current which is

sometimes called amperage because we

measure it in amperes or amps or

sometimes milliamps which is a

thousandth of an amp

and then thirdly we've got power which

is sometimes called wattage because we

measure it in watts or horsepower if

it's a car you can also see there in the

table i've got the common symbols that

are used when we talk about these in

equations

these three concepts can sometimes be a

little bit tricky to understand and

plenty of people have tried to explain

it over the years i'll try and find some

videos and include a link in the

description

but generally they're going to involve

some sort of analogy with water pipes

the voltage in the battery is like

pressure in a pressurized tank there's

potential there but there's nothing

flowing

if you connect that tank battery to pipe

wires then the pressure will force the

water or the electricity to flow through

the pipes

the amount of pressure and the size of

the pipe for the resistance of the pipe

will affect how fast the water flows

or something like that the three things

that are probably the most important to

understand for now is firstly that power

equals voltage times current or p equals

vi

so if you've got more of voltage or

current then you've got more power and

if you've got less of it you've got less

power

if you keep the voltage the same but you

double the current you've doubled how

much power you're using or if you keep

the current the same and half the

voltage you halve the power

secondly for any particular application

the voltage is usually kept constant and

the current will fluctuate up and down

depending on what the load is for

example until very recently every single

usb device out there ran at 5 volts

but they would all use different

currents so a wired keyboard might only

use a few milliamps but say you had

something like a usb powered heater that

might pull a few amps but no matter how

many devices you're plugging in and

unplugging they're always going to be 5

volts

and thirdly and this is probably the

most important one to understand right

now when a power supply gives you a

current or a power rating that's the

maximum amount of power that it can

safely provide and when a device or a

component gives you a power or current

rating that's the maximum amount of

power it will ever draw

so that last point is going to be key to

many of the decisions we make as we're

building our robot

when we start to exceed electrical

ratings things tend to stop working and

get hot and the worst case catch fire so

when we're choosing our batteries our

components our devices our connectors

and our wiring we want to make sure that

everything is designed to work correctly

together

okay so you want to start wiring up a

circuit for a robot the first place to

start is with the voltage we've got to

figure out what voltage our robot is

going to operate

and in this case we're actually going to

have two different voltages inside our

robot

first up is going to be 5 volts

many microcontrollers like the raspberry

pi and the arduino are based on a 5 volt

input and all of the usb devices will be

using operator 5 volts too sometimes

you'll see 3.3 volt components crop up

we're not going to worry about that for

now

but you should be aware that it's a

thing the question is though where do we

get five volts from maybe a battery

this is where we'll start to run into

some problems you see five volt

batteries just don't exist for chemistry

reasons

and even if they did exist the voltage

would probably fluctuate depending on

the charge and other factors and these

devices often require a very precise 5

volts

and the other thing is we'll also need

power for our motors and generally

they're going to need a lot more than 5

volts

so the solution then is to use a

regulator

this is a component that takes a

different voltage usually higher

sometimes lower but almost always higher

and it converts it to a precise and

regular output voltage in this case 5

volts and there are two main types of

regulators out there there's linear

regulators and switching regulators

linear regulators are simple small and

cheap in fact the arduino and the motor

driver board i'm using both include one

on board just for the sake of

convenience

the problem is that they're not very

efficient especially when you've got a

high input voltage and if you're pulling

a lot of current through it and because

of that i'd recommend a switching

regulator sometimes called a switch mode

power supply or a buck converter we'll

talk more about that pretty soon when we

look at current so what goes into our

regulator well that's our supply voltage

and so the next question is going to be

well what voltage should that be the

first step is to look at what other

components we have that are going to

draw power

in this case for me it's going to be my

motors which are two dc motors that get

the supply voltage via a motor driver

chip

so we want the supply voltage to be the

right voltage for what our motors are

rated for now dc motors are pretty

resilient they'll pretty happily take

voltage that's over or under what you

want but you have to check what your

motors are capable of

12 volts is usually a pretty safe bet

there are a lot of motors out there that

are designed to work with 12 volts but

sometimes you might find 6 volts or 24

volts or something else so it will

depend on what your project is

so that's how voltage is sorted out 12

volts coming in going to the motors and

going to the regulator which gives us 5

volts for the rest of our components but

what about current like i mentioned

before current is going to dictate a lot

of the decisions that we make when

building our robot we could go for a

really small efficient low current robot

or we could go for broke build a big

beefy robot with massive motors that

pull heaps of current

whatever we're doing we just want to

make sure we're being careful and aware

as we design it

let's start by focusing on our five volt

components again we want to make a list

of all the components our robot is going

to have and try to get a rough estimate

for the maximum current they can each

draw

now for some components it might be hard

to find a data sheet this can be a bit

difficult we just need to make do with

what we can

here you can see my estimates but don't

trust these make sure you do your own

calculations

you can see the total is 4.7 amps which

i'll just round up to five

you can also see that most of this comes

from a few heavy hitters the pi the

lidar the depth camera and the lcd

screen so if you don't have some of

those components then your current draw

is going to be a lot lower

once we know how much current our 5 volt

components are going to draw up to 5

amps in this case we need to make sure

we choose a regulator that's capable of

supplying this

even though the regulator is only

forwarding on power that's come from

another source there's still a limit to

how much it can safely pass through so

our regulator needs to be capable of

supplying 25 watts of power

i'll be using this 25 watt regulator and

we'll take a closer look at it in the

next video when we assemble everything

so now we can kind of treat this whole

part of the circuit as one big 25 watt

component and if we're trying to pull 25

watts of power out of the regulator we

need to make sure we're putting 25 watts

of power into it

now if we're drawing exactly 5 amps at 5

volts out and the regulator was 100

efficient and our power supply was

exactly 12 volts going in then we can

calculate that the current draw from our

power supply would be

2.083 amps

in reality though there's always going

to be efficiency losses and we won't

always have exactly 12 volts since our

battery can fluctuate so i'm going to

round this number up to 2.5 amps to use

for future calculations

so that's our 5 volt components what

about our motors

the motor current draw is going to be

really dependent on the sort of motors

you've chosen and what your robot's like

how heavy it is how hard the motors have

to work that sort of thing and that's

because the more torque that a motor has

to put out the more current that it's

going to draw

now the maximum amount of current that

it's going to draw is when you stall the

motor so that's like if this motor was

spinning around right now and i just

grabbed the output shaft and held it

still and just let the power run through

it that current running through is

called the stall current and if you let

that much current run through your motor

for more than a moment it's probably

going to wreck it so we don't want to go

anywhere near that to find out what the

stall current is without breaking your

motor we want to take a look at the data

sheet it should tell you the stall

current and probably also some other

currents at lower torques that you

should be using

so you can see here the motor that i

plan to use has a stall current of 1.8

amps and a rated current load of 0.75

amps

and remember that we've got two motors

so the total current draw from our

supply is going to be two times that so

in this case the maximum amount of

current that i'll be pulling from my 12v

supply is 3.6 amps

you also want to make sure that your

motor driver is capable of supplying

that much current to the motors we'll

cover that in a couple of videos when we

get our motors up and going so the

maximum amount of current required from

our 12 volt power supply is going to be

6.1 amps and since this is a mobile

robot that power is almost certainly

going to be coming from a battery

so how do we figure out what kind of

battery we use

so if we're looking for a battery that

can supply about 12 volts and at least 6

amps of current then our most likely

candidate is going to be a lipo battery

if you're not familiar with lipos i'll

try and find a good video to include in

the description there are five things

though that it's worth knowing about our

battery

first up is a warning

lipo batteries pack a lot of power and

energy into a pretty small package which

is great for powering a robot but also

poses a safety risk whenever you're

working with lipos you want to be

careful don't let the charge get too low

don't let the wires short on anything

make sure you charge them with a proper

charger in a fireproof area with the

balance leads in under supervision store

them safely etc

secondly is the s number this is the

number of cells in the battery see the

battery you buy is actually a bunch of

smaller cells joined together so this

battery says 3s on it that means it's

three cells joined together to get a

higher voltage

speaking of voltage each cell of a lipo

has a nominal voltage of 3.7 volts so

our 3 cell battery is going to have a

total of 11.1 volts

but lipos actually vary a lot in their

voltage depending on how charged they

are so when they're fully charged each

cell is going to have 4.2 volts so

that's 12.6 total for our 3 cell battery

and then the voltage is going to drop

down as we use the battery

now if you let it get too low it can be

bad for the battery or even dangerous so

i don't like to let mine get below 10

volts make sure you're checking the

voltage regularly and also if anyone

knows of a good cheap simple

adjustable low voltage cut-off unit for

use in small robots like this let me

know because i'd like to include it

the next number to look at on our

battery is the capacity this is usually

measured in milliamp hours

that's how much current you could

continuously draw from the battery to go

from full to empty in exactly an hour

and if you're pulling more current it'll

last less time so this 3000 milliamp

hour battery could run at six amps or

six thousand milliamps for half an hour

or 30 minutes

but you don't want to run it the whole

way down you want to aim to maybe use

two thirds of that and like i said

before keeping an eye on the voltage as

you go

finally the discharge rating or the c

number tells you the maximum current

that can be drawn from the battery

but this number is a bit weird the way

you calculate it is you multiply the

capacity of the battery by the c number

so this battery is 3 000 milliamp hours

and 20 c

so that's 60 000 milliamps or 60 amps

which is plenty that's like 10 times

more than the 6 amps that i calculated

i'll need

now if you want you can be doing all of

your testing using a battery but you'll

pretty quickly get tired of having to

charge it all the time so that's why i

recommend while you're doing bench

testing to have some kind of mains

powered power supply now the best option

is probably to get a proper bench power

supply like this one here

they're not too expensive and they let

you adjust the voltage and the maximum

current to whatever you need i should

probably get around to getting one for

myself but if you can't afford that

there are plenty of other choices out

there you can get dedicated high current

12 volt supplies

you can use a computer power supply you

could probably use a normal ac to dc

wall wart but make sure that you check

that the current and voltage are correct

first

or if you got really stuck you could

even use something like a car battery

even though it's still only a battery

it's going to drain a lot slower than

one of these will that's all the main

components of our circuit covered but

there are a few other parts of our

circuit infrastructure that we want to

make sure we talk about before we're

done don't switch off now because these

are some of the most important parts for

safety something to make sure we don't

forget is our wiring and our connectors

we have to make sure that they are all

rated for the currents that we're using

and i say current because the voltage

doesn't matter it's all about the

current when it comes to this so i'll

include a link in the description to a

table where you can see for a particular

gauge a particular thickness of wire how

much current that wire can safely carry

and for connectors you want to be

checking their data sheets for example

this xt60 connector is rated for 60 amps

but this rcy plug is only rated for 5

amps and breadboards and jumper wires

should only be used for very low

currents in the milliamps

related to this is something i mentioned

in the last video which is that the

raspberry pi has a limit on how much

current can pass through the usb ports

that are on board and so that's why i'll

also be including an external usb hub so

we can supply extra power to this and

get all the current we need to our

devices

once we've got safe wiring and

connectors we want to make sure we add a

power switch to our robot this lets us

turn it off when we're not using it so

that we can safely disconnect and

connect the battery without risk of

shorting things out

and the last thing we need to add to our

circuit diagram is a fuse

without a fuse if positive gets

connected to negative somewhere in the

circuit maybe there's a loose wire or a

failure in a component

it creates what's called a short circuit

and a huge amount of current will flow

from the battery through all the wiring

it'll basically use as much power as it

possibly can and burn out the wiring or

worse set the battery on fire

that's generally regarded as something

to avoid so by adding a fuse we're

creating a deliberate failure point in

our circuit

if the current gets too high it'll burn

out the fuse break the short circuit and

keep us safe

we don't want it to burn out under

normal use though so we need to make

sure we choose a fuse that is rated for

the current that we have in our circuit

and that way it'll let through current

up to that point and then burn out if

the current is going beyond that

now keep in mind that this fuse is

designed just to protect the wiring and

the battery it won't necessarily protect

your components from short circuits

there are fuses that we can install for

that but we're not going to talk about

that right now and remember just like

with everything else in the next video

i'll be showing you the fuse that i'm

using in my circuit

so i think that'll do it for the theory

side of things in the next video i'll be

wiring everything up and we'll be able

to take a closer look at some of the

components make sure you subscribe so

that you don't miss out on that

now i've tried to cover everything that

i can but i'm sure there are things that

you think i should have mentioned and

you'll let me know in the comments but

if there's anything particularly

relevant to safety please leave a

comment letting me know so that i can

update the description and if you're

really quick i'll try to get it into the

next video otherwise i'll catch you next

time