It is an electrical device whose main job is to provide power to an electrical load. It has the means of providing the load with a range of stable voltages and currents.

The power supply can be used by anyone from the maker in their garage, to the experienced engineer prototyping new ideas.

But, good quality power supplies can be quite expensive and acquiring one might leave a dent in your bank account.

Are there any alternatives to using a power supply?

Can you use a battery charger as a power supply?

Yes you can use a battery charger as a power supply. A battery charger is effectively a power supply. As long as the battery charger can provide the sufficient amount of voltage and current to the electrical load, it can be used as a power supply. There are some differences and considerations to take into account when using a battery charger as a power supply which  shall be discussed in this article.

What is the difference between a power supply and a battery charger?

Whether you are a weekend hobbyist, or engineer, you are going to need some sort of way to power your projects. 

You have many options when it comes to power sources, whether it be temporary (like a battery) or a more permanent solution (like a power supply).

Before diving into the details of why you can use a battery charger as a power supply, let’s take a closer look at both these devices individually and see what sets them apart in their main purpose. 

Power supply

The power supply is the heart of any electrical and electronic system. 

Just like the heart pumps blood to the rest of the organs in the human body, the power supply pumps power to the rest of the components in that system. 

A power source is anything that has the ability to provide electricity in the form of voltage and current. 

But, it needs to be able to supply a stable voltage and current. If the power supply has trouble supplying sufficient power it is going to cause inefficiencies in the system. 

A power supply is one type of power source designed to ‘supply’ power to an electrical or electronic load (as pictured below).

It will have an input power connection which receives energy in the form of electrical current and then delivers this to its outputs where a load can get connected. 

An example of power supply is one used in your computer. It is designed to receive power and distribute it to the rest of the internal components of your computer. 

There are two types of power supply available; DC-DC and AC-DC.

A DC-DC power supply converts an incoming Direct Current (DC) into another outgoing Direct current. 

These types of power supply are less commonly used.

An AC-DC power supply is the most commonly used of the two. It converts an incoming Alternating Current (AC) into an outgoing Direct Current. 

Electrical power delivered to homes is presented at power outlets in the form of alternating current. But, most (if not all) electrical and electronic devices need a direct current (DC) to function.

So, AC-DC power supplies are most suited for these applications. 

Below is a flow diagram of how an AC-DC power supply works. 

Benchtop power supplies are also another form of power source used in electronics.

A benchtop power supply is great for the early development stages (prototyping) of projects, or when you are testing different voltages and currents. 

This is because the power supply has the ability to provide a range of voltages and currents at its outputs depending on the power requirements of the load.

Battery charger

The emergence of mobile technology has enabled us to take our devices and use them outside of our homes without the need of an electrical cord and power outlet. 

You can be hiking in a forest and still browse the internet on your smartphone.

Inside every mobile device is a Rechargeable battery. Unlike a normal disposable battery that can only be used once, a rechargeable battery can be used multiple times.

The ability for it to be used multiple times comes down to its internal chemical composition. 

But, a rechargeable battery cannot just recharge by itself. 

It requires a Battery charger which has the ability to provide energy to ‘recharge’ it. 

The battery charger’s main purpose is just that, to recharge a mobile device’s battery. 

You might be reading this article on your smartphone, or laptop and sooner or later your battery is going to run out of charge. So you will need to use a battery charger to recharge it. 

There isn’t one specific type of battery charger used for all mobile devices.

They come in a range of output voltages and currents which depend on the size of the battery used in the mobile device. 

For example, a smartphone battery is usually rated at 3.8 volts, while a laptop battery tends to be 11.1 volts. 

So, each of these devices will need a separate battery charger designed specifically to be able to recharge it.

Why you can use a battery charger as a power supply

Now that we have taken a look at the power supply and battery charger, we can look at why it is possible to use a battery charger as a power supply. 

As seen earlier, the battery charger has the task of recharging a dead rechargeable battery. 

So, why can you use a battery charger as a power supply?

We know that the power supply has the function of providing power (voltage and current) to an electrical load. 

The battery charger is essentially a power supply, only that it’s overall purpose is different to that of a conventional power supply. 

However, it functions the same way that a power supply does. 

It has an input power connection to receive energy (in the form of current) and an output which gets connected to an electrical/electronic load (in this case, mobile devices).

So a battery charger has the ability to be used as a power supply. 

Can you use any type of battery charger as a power supply?

But, before we proceed, there is a bit more to using any battery charger as a power supply. 

In the world of battery chargers you typically have two types;

The first type (let’s call it Type A) is commonly used for mobile technology such as smartphones, digital cameras, laptops etc. 

This type of battery charger only has the job of holding a fixed voltage. The charging circuit is contained within the device itself near the battery. 

The second type of battery charger (Type B) like ones used for portable power tools (where the battery can be removed), has the charging circuit contained inside the charger. 

Of the two types, Type A is more suitable to be used as a power supply as Type B is a bit more complex. 

Determining which type of battery charger you can use as a power supply

As you will have different types of battery chargers lying around in your home, figuring out which you can use as a power supply might be a bit confusing.

But there are some general guidelines you can follow to determine if you can use a particular battery charger as a power supply. 

• Battery chargers that have a Barrel Connector , can be used as a power supply. Voltage ratings for these types of chargers will usually be 12 or 5 volts. Their current ratings can range from 350mA to 2.5A
• Battery chargers with a USB output can be used as a power supply. Their voltage ratings are usually 5V. Current ratings can range from 500mA to 2.1A.
• Laptop chargers can also be used as a power supply, however, they tend to have strange voltages like 15.4 and 19.7 volts. You might require a DC-DC step-down converter to adjust the voltage to something that is more compatible with your project.

What are the requirements when using a battery charger as a power supply?

While you can use a battery charger as a power supply, there are some requirements to consider before doing so.

Voltage and current requirements

The first thing you will need to check before using a battery charger as the main source for your project is whether it has sufficient voltage and current. 

Let’s take a look at a simple example to better understand what I mean.

Say you need to power a load (a lamp in this example). 

Like every electrical and electronic load, it requires a certain amount of voltage and current to operate. So, let’s assume this lamp needs a voltage of 5V and a current of 1A.

So, in order to power this lamp sufficiently, we need to provide it with a voltage of 5V and current of 1A.

Since there are many different types of battery chargers, you will need to select one that has output voltage and current ratings that match the load you are powering.

Note, avoid choosing a battery charger that has an output voltage rating higher than the voltage rating of the load you are powering as you run the risk of damaging it.

Stable power out

A good power supply needs to supply a stable voltage and current to its load. 

If it cannot do so, it is going to cause the electronic system to be inefficient and you will encounter issues of your project randomly shutting off as it does not have enough power.

The same can be said for a battery charger. 

You will need a battery charger that has the capability of providing a stable power output so that you avoid the problems mentioned above. 

Battery chargers that do not cost much can be an issue as they are manufactured using cheaper parts and materials. 

While you save on money, you forfeit the stability of output power. 

So fork out a little bit more money and invest in a good quality battery charger. 

Benefits of using a battery charger as a power supply

So, you can use a battery charger as a power supply. 

Great!

But, why would you want to do so? 

Why not just buy a power supply?

Well, there are many benefits to using a battery charger as a power supply. 

The first benefit being that a battery charger is less expensive than a power supply. You can get yourself a good quality battery charger for under $50.

Next on the list of benefits is that battery chargers are readily available. You will no doubt have a couple of them lying around. You will also be able to find them at your local electronic store. 

Finally, battery chargers are smaller than a power supply. This makes it easy to set up a project without having to lug around a power supply.  

Can you use a USB charger as a power supply?

Yes you can use a USB type battery charger as a power supply.

As we saw earlier, a USB battery charger is a Type A charger which holds a voltage making it easier to use as a power supply.

These types of chargers are commonly used with mobile devices like smartphones, digital cameras etc. 

Their output voltage is usually 5V with output currents that range from 500mA to 2.1A. 

The post Can I use a battery charger as a power supply? appeared first on Electronic Guidebook.

With the emergence of rechargeable batteries, devices can be taken anywhere and charged on the go.

A Vape is no different. It is an electronic device designed to be used on the go, and has rechargeable batteries so you charge it no matter where you go.

There might be certain scenarios where you will not have a wall outlet available to charge your vape.

So, you might be wondering, can I charge my vape with a power bank?

Yes, you can charge your vape with a power bank. As long as the power bank has a USB output, sufficient output voltage, and capacity, you will be able to charge your vape no problem.

If you want to understand a bit more of what it takes to charge a vape using a power bank, read on.

Why it is possible to charge your vape with a power bank

A Vape is an electronic device designed to be used on the go.

It would be pointless if it came with a cord which always had to be plugged in for you to use it, resulting in you being stuck in your room at home smoking away (might as well invest in a Hookah)

So, lucky for you and me, vapes are powered using batteries making them mobile.

But, the beauty is that vapes are powered using Rechargeable batteries. 

This means once they run out of charge, they can be recharged. 

Not just once, but many times!

Charging the vape requires a power source. This power source comes in the form of Wall chargers that you plug into a power outlet.

The wall charger is created to charge devices that have rechargeable batteries like your mobile phone, laptop, vape, digital camera etc.

It has the ability to provide the power required to ‘recharge’ the batteries of electronic devices.

The power bank

Some smart person realised that power outlets might not always be available like when you are camping, or maybe going on a hike.

So, the Power Bank was invented to ease our pain.

It is essentially a portable wall outlet that you can take with you and charge your vape. 

Its main purpose is to provide power to be able to charge mobile devices when there isn’t a power outlet available.

Note, the power bank itself is a rechargeable battery and will have to be charged as well.

How a power bank can be used to charge vape

So, what does it take to charge a vape using a power bank?

To charge the vape using a power bank, the power bank will need to have sufficient voltage output requirements that match the vape’s battery voltage specifications. 

The standard nominal operating voltage for most vape batteries is 3.6 volts.

So, in order to be able to charge the vape, the power bank will need to provide an Output voltage that matches or is greater than 3.6 volts. 

In general most mobile devices use voltage that ranges from 3.6 – 5V. 

Because of this, the majority of power banks have an output voltage of 5 volts and is why they can be used to charge a vape. 

How long does it take a power bank to charge a vape?

The faster the power bank can charge your vape the better. 

How fast it takes a power bank to charge a vape comes down to two factors;

1. Output current of the power bank
2. Battery capacity of the vape

Output current (power bank) – Is the maximum value of current that the power bank can supply at its output 

Battery capacity (vape) – Rechargeable batteries have a characteristic that determines how much charge they can store known as battery capacity which is given in either Amp-hours or Milli-Amp-hours.

This unit lets us calculate how long a battery will last for depending on how much current it is supplying. 

For example, say your vape battery has a capacity of 1000mAh and is supplying a current of 10mA to power the vape, the battery will last for 100 hours (1000/10).

This formula can also be used to calculate how long it will take to charge the battery. 

Calculating how long it takes to charge a vape with a power bank

We can use the above factors to calculate roughly how long it will take a power bank to charge a vape. 

Standard vape batteries come with a battery capacity of 3500mAh. 

Below are calculations of different times which vary depending on the output current values of the power bank. 

As you can see, the greater the output current, the faster the power bank will charge your vape. 

Tip on charging a vape faster with a power bank

You might be tempted to use the vape when charging it with a power bank as it is portable as well. But, doing so is going to increase the time it takes to charge.

So, if you want to further increase the speed at which the power bank charges you vape, turn off your vape when charging. 

How many times can you charge a vape with a power bank?

Another important factor to consider when you take your power bank and vape on your next adventure, is how many times the power bank will be able to charge the vape after only being charged once. 

How many times a power bank can charge an electronic device like a vape, comes down to the battery capacity of both devices. 

For example, let’s use the same vape battery capacity from the above example (3500mAh). 

If we had a power bank with the same battery capacity (3500mAh), it would only be able to charge the vape once. 

We get this value by dividing the battery capacity of the power bank by the battery capacity of the vape.

If we increased the battery capacity of the power bank to say, 15000mAh, we would now be able to charge the vape around 4 times! 

While the advantage is obvious in that the power bank will be able to charge your vape multiple times, the downside is that it takes longer to charge. 

Do I need a special type of power bank to charge vape?

Cool, so you can charge your vape using a power bank!

But, do you need a special brand of power bank?

No, you will not need a special brand of power bank to charge your vape.

As long as the power bank has sufficient power at its output (voltage ratings) that match (or is higher) than that of the vape’s battery, you will be fine.

Do I need an expensive power bank to charge a vape?

What about the quality of the power bank?

Do you need an expensive power bank in order to charge my vape? 

We all want to get the best bargain when we buy something new. But, if we pay too little for an item we are going to suffer in the long run.

Nowadays you can buy all sorts of electronics for dirt cheap prices. Cheap electronics are possible because they use cheap materials to create them.

This means they will malfunction sooner than later.

While you do not need an expensive power bank to charge your vape, I do recommend buying a good quality power bank from a reputable brand.

You might have to fork a little more money, but this will save you down the road as you wont be buying more power banks to replace the cheap ones that keep malfunctioning. 

Is it a good idea to invest in a power bank to charge your vape?

The simple answer is yes!

Having a power bank has many advantages.

Advantage #1 using a power bank to charge vape: Charge on the go

The first most obvious one is that you will be able to charge your vape no matter where you go. 

If you are an avid adventurer as well as a vape connoisseur, the power bank will solve your problem when you are stuck in the middle of nowhere with no power outlets, and your vape battery is about to perish.

Advantage #2 using a power bank to charge vape: No need for replacement batteries

Second, you will not have to carry a bunch of replacement batteries. 

Also, lithium-ion rechargeable batteries pose a risk of catching fire especially when carried loose.

The power bank evades this problem by being able to recharge the existing batteries in the vape. 

Advantage #3 using a power bank to charge vape: Charge other devices

Last and not least, you are not restricted to just charging your vape with the power bank. 

No doubt you have a mobile phone. You will also be able to charge it and other small electronic devices with the power bank.

Considerations when charging a vape with a power bank

If you do not already have a power bank and are thinking of purchasing one, below are some factors to take into consideration. 

Output voltage – Make sure the output voltage of the power bank matches or is a little higher (usually 5V) than then vape’s battery. 

Speed – If you need the power bank to charge your vape fast, opt for one with a higher output current (and do not use the vape while charging)

Multiple charges – you might be away from a power source for a long time and need a power bank to charge the vape multiple times. In this instance you will need a power bank with a large capacity. 

Portability – You don’t want to have to lug around a power bank the size of a brick. This would be counter intuitive. So, you will have to find a power bank that is decent size as well as being able to tick your other criteria.

The post Can I charge my vape with a power bank? appeared first on Electronic Guidebook.

Your chances of calling for help are very limited.

A Power Bank would be able to solve your problems.

It is a portable battery charger capable of charging many devices such as mobile phones, digital cameras, portable speakers, bluetooth headphones and much more.

A power bank contains a rechargeable battery capable of storing charge which can then be later used to charge the electronic devices mentioned above.

But, is a power bank a lithium ion battery? Lithium Ion batteries are the most commonly used rechargeable batteries used in power banks due to them having a high energy density and low discharge rate as well as being cost effective. 

There are other types of rechargeable battery available which can include Lithium-Polymer (Li-Po) and Nickel-Cadmium (Ni-Cad) that are used for power banks. 

The power bank

The power bank helps solve many problems, the main one being that you can charge your devices when you are not at home or office where a power outlet is located.

It gives you peace of mind when travelling far places where these power outlets become harder to find.

Let’s take a close look at the power bank. 

At the heart of the power bank is the Rechargeable battery. 

Without this main component the power bank would be useless. 

A rechargeable battery has the ability to be charged, discharged into a load and then recharged multiple times.

Normal batteries (disposable ones) can only be used once and then have to be disposed of not making them a viable option for power banks. 

Other parts of the power bank include; Charging circuit, Battery protection circuit, and Boost converter.

Charging circuit

The main purpose of the charging circuit is to provide a constant DC (direct current) or pulsed DC power to the rechargeable battery of the power bank.

Battery protection circuit

There are going to instances when you charge the power bank and forget to remove the charger, leaving it plugged in longer than required.

Lucky for us, the battery protection has the job of protecting the power bank’s battery from overcharging.

It also protects the battery from high temperatures.

Boost converter

The boost converter circuit in the power bank steps low voltages between 3.7 – 3.85 volts to the standard operating voltage of 5 volts (which is used by most electronic devices). 

Why do power banks use a lithium ion battery?

Lithium ion rechargeable batteries aren’t the only batteries available when designing a power bank, however, they are the most common.

Early on, Nickel-Cadmium was the go rechargeable battery for portable equipment and wireless communication.

Lithium ions are now the preferred battery of choice, being used in almost all portable electronics and they can even be found in Electric vehicles. 

The Lithium Ion battery contains electrolytes which lithium ions travel through from the negative to the positive electrode. 

Compared to Nickel-Cadmium batteries, Lithium Ion batteries have a higher energy density (typically double), but there is room to increase the energy density further. 

Also, the lithium ion battery has lower maintenance compared to other rechargeable batteries. There is no memory and schedule cycling is not required to prolong the life of the battery. 

Below are other characteristics of the Lithium Ion Battery;

Lithium- ion vs Lithium polymer power bank. Which is better for a power bank?

We saw that Nickel-Cadmium batteries were used earlier on in the infancy of portable technology, and nowadays Lithium Ion batteries are the popular choice. 

But, there is another rechargeable battery that is quite popular, and that is the Lithium-Polymer rechargeable battery. 

Which battery is better for a power bank? 

Let’s take a look at the advantages and disadvantages of both batteries which will give us a better indication of which is the better choice for a power bank.

Lithium-Ion Advantages

• High energy density
• Low self-discharge 
• Low maintenance
• Speciality cells can be used for high current applications

Lithium-Ion Disadvantages

• Requires protection circuit to protect against over voltage and currents 
• Can age relatively fast if not stored in cool environments
• Expensive to manufacture
• Still in evolutionary phase (lots of improvements are being made)

Lithium-Polymer Advantages

• Sleek, compact design 
• Flexible
• Lightweight
• Improved safety

Lithium-Polymer disadvantages

• Lower energy density and decreased cycle count
• No standard sizes
• Higher cost-to-energy ratio

So, there are the advantages and disadvantages of both the batteries. 

But, how do we know which is better to use in a power bank?

There are a couple requirements to consider of what will make an effective power bank which is ultimately determined by the battery. 

• Cost
• Life cycle
• Capacity 

Cost

First on the list is cost. 

With anything you buy, you do not want it to cost you an arm or leg. 

The same can be said when buying a power bank. 

While both batteries are relatively expensive to manufacture, the cost to energy ratio of the Lithium Polymer battery is higher. 

So, it is more cost effective to use a Lithium-Ion battery for a power bank as it will cost you less to get the same amount of energy as a Lithium-Polymer battery. 

Life Cycle

It would be pointless if you could only use your power bank 10 times and then have to dispose of it. 

The aim is to have a power bank that will last you a long time. 

The life cycle of a power bank is the amount of times you can charge and discharge it before the battery wears out. 

There are many factors that determine the life cycle of a battery like capacity, storage, etc.

But, generally, Lithium-Ion batteries are known to have a higher cycle count compared to their Lithium-Polymer counterparts. 

Capacity

Finally on the list of requirements for an effective power bank is its capacity

The capacity of a power bank is the amount of charge it can store and thus charge other portable electronic devices.

It wouldn’t make sense if a power bank held less charge than your mobile phone. 

This would mean that you would have to charge the power bank a couple of times in order to fully charge your mobile phone rendering the power bank ineffective. 

The capacity of a power bank correlates directly with the energy density of the battery it uses. 

The higher energy density of the battery the more power it will be able to store and therefore charge your portable electronic device multiple times. 

Lithium-Ion batteries have higher energy density than Lithium-Polymer batteries.

So, you can see that the Lithium Ion meets all three requirements which determines the effectiveness of a power bank making it the better option.

Health and Safety concerns with lithium ion battery power banks?

While they have their many advantages and reasons to be used in a power bank, Lithium-Ion batteries are known for exploding and catching fire.

Due to this they have many restrictions when taking them on flights especially as carry-on luggage.

So, check with you the airline you might be flying with for what restrictions they have for power banks that use Lithium-Ion batteries. 

Always store the power bank in a cool place and out of direct sunlight.

The post Is a power bank a Lithium ion battery? appeared first on Electronic Guidebook.

A resistor can provide many functions in a circuit, but its main purpose is to limit current. 

However, when it comes to limiting current, power is dissipated in the form of heat.

But, which resistor dissipates more power? The amount of power that a resistor comes down to a lot of factors, but a smaller resistor will dissipate more power due to the fact that it has a lower surface area and a higher current flowing through it. 

In saying that, there are other considerations to take into account which comes down to Ohm’s Law, material the resistor is made of, and surface area of the resistor. 

I will cover these below. 

Why do resistors dissipate power

To begin with, let us understand why resistors actually dissipate power. 

Without getting into too much detail, you might be aware of the first Law of thermodynamics, also known as the Law of Conservation of energy which states that energy can neither be created or destroyed.

It can either be transferred or changed from one form to another. 

For example, the sun transforms nuclear energy into heat and light. 

When current flows through a resistor, slowing or limiting it causes a transfer of energy. The energy transfer in this instance is from kinetic (vibration of atoms or charge), to heat. 

The slowing of molecules largely depends on the material that the resistor is made of which tends to be a conductor (as current needs to flow through it as well)

All conductors have some form of ‘resistance’. 

Therefore, the resistor dissipates power in the form of heat. 

What determines which resistor dissipates more power?

Now that we know why a resistor dissipates power, we can look at what factors determine which of the resistors will dissipate the most power.

The first major factor that will determine how much power a resistor will dissipate comes down to Ohm’s law.

Ohm’s law is a law that states that the current through a conductor (between two points), is proportional to the voltage between those two points. It can be seen in the formula shown below.

This fundamental formula is used when designing and diagnosing circuits. 

It lets you calculate voltage, current , and resistance of a circuit or at a specific component in a circuit. 

Another formula that is important to us in determining how much power is dissipated by a resistor is shown below.

There are many ways to calculate power dissipation, but these are the two most common using voltage, current and resistance. 

Next, let’s take a look at how you would go about calculating how much power a resistor dissipates using these formulas which will give an indication of which type of resistor dissipates more power. 

How do you calculate how much power a resistor dissipates

Let’s take a look at an example of how to calculate how much power a resistor dissipates in a simple circuit. 

Below is a simple circuit with a voltage source, and resistor. 

The good news is that knowing how to calculate power dissipation in this simple type of circuit will apply to every circuit no matter its complexity. 

So, we will go about finding how much power the resistor in this circuit dissipates using the two formulas we saw earlier which are; V= IR and P = V²/R.

Below are the list of steps required to find the power dissipation of the resistor R1 in the circuit above:

1. Find the total current in the circuit
2. Find the voltage across the resistor using the current value (since this is a series circuit, the current is the same throughout the whole circuit)
3. After the voltage is found across the resistor, use that voltage and value of resistor R1 to find the Power dissipated by the resistor.

STEP 1:

First we need to find the total current in the circuit. This requires us to use the V=IR equation.

Since we know the values of V and R, we can rearrange the formula to make I the subject which gives us the following formula I = V/R₁.

So plugging the values into the formula I = 5 /10, gives us a current of 0.5 amps.

STEP 2:

Now that we have the total current in the circuit (since this is a series circuit where current is the same throughout the circuit), we can calculate the voltage across the resistor. 

We will go back to using the formula of V = IR. 

In this instance, the value of R in the formula would be the value of the resistor we are trying to find the voltage across which is 10 ohms in this example.

So, using the current we just calculated, and the value of resistor R₁ in the formula, V = 0.5 x 10, we get a voltage value of  5 volts. 

This tells us that there is voltage drop of 5 volts across resistor R₁. 

STEP 3:

The last and final step requires us to use the formula P = V² / R.

V in this equation is the voltage drop value across resistor R₁(5 volts), and R is the value of R₁ (10 ohms).

Plugging these values in the equation P = 5² / 10, gives us a P value of 2.5 watts.

This is the value of how much power the resistor dissipates in the circuit in question. 

Why a smaller resistor dissipates more power

From the example above we saw that a 10 ohm resistor dissipates 2.5 watts of power. 

What if we decrease the value of the resistor from 10 to 5 ohms while keeping the voltage value the same? 

What happens to the amount of power dissipated across the resistor?

The value of power now increases from 2.5 watts to 5 watts.

This is due to the inversely proportional relationship between R and P in the P = V² / R equation.

An increase in R will see a decrease in P, and a  decrease in R will result in an increase in P.

Also, another reason a smaller resistor will dissipate more power comes down to its surface area.

A smaller, or lower value resistor has a lower penetration of the magnetic field which leads to an increase in current flow within a smaller surface area.

Due to this there is greater power dissipation in the form of heat loss.

Do bigger resistors dissipate more power that smaller resistors?

As we saw with the examples above, a smaller resistor will dissipate more power due to Ohm’s law, as well as its physical dimensions.

But, why are bigger resistors used for higher power applications? Does that mean that they dissipate more power?

The main reason a bigger resistor is used in higher power applications is because of its ability to handle those high levels of power. 

This comes down to its size and material. They are specifically designed for high power applications. 

A bigger resistor unlike a small resistor, has a larger surface area giving it the ability to dissipate heat and therefore power better. 

This is why you would use a larger resistor in high power applications because they can dissipate that power more efficiently.

Do all resistors dissipate the same amount of power?

The simple answer is no. 

All resistors dissipate different amounts of power.

As you from earlier, this comes down to the resistance value which is influenced largely by what material it is made of, as well as its size. 

All resistors have their own power rating, which is labelled on the resistor’s packaging, the specification section online or on its datasheet. 

Power rating of a resistor

So, every resistor dissipates different amounts of power. 

Lucky for us, this value is given to us. 

It is known as the resistor’s Power Rating or Wattage Rating.

Every resistor has a maximum power rating which is governed by its physical size. The greater the surface area, the better its ability to dissipate power in the form of heat.

This rating is defined for ambient temperatures of 70 degrees celsius (158 degrees fahrenheit) and above.

Exceeding the  maximum power rating of the resistor will cause it to be damaged. 

While resistors have colour coding that indicate its resistance value and tolerance, this colour coding does not indicate the power rating of the resistor. 

You will find the power rating on the packaging that the resistor comes packed in. Or, when buying them online, the specifications section of the resistor should indicate the power rating. 

Does a resistor dissipate more power in series or parallel?

You might be aware that there are two types of circuit configurations that a resistor can be used in; Series or Parallel (or a combination of both).

In a Series configuration, the current is constant throughout the circuit, whereas in a parallel configuration, the voltage is constant. 

So, does a resistor dissipate more power in series or parallel?

The configuration a resistor is subject to does not matter when it comes to power dissipation.

It comes down to the voltage and current that the resistor is subject to in either configuration. 

The great news is that Ohm’s law and the power formula can be used in both configurations to calculate the power that the resistor will dissipate and then you can go about choosing a resistor with the right power rating accordingly.

Does the material that the resistor is made of affect how much power it dissipates?

The material is one of the factors that determines how much power a resistor will dissipate. 

There are three typical types of resistors ; Wirewound, Metal Film, and Carbon.

Wirewound resistors are used for larger power resistors with higher power ratings, whereas Metal film and Carbon resistors are used for lower power applications. 

No matter what type of material, Ohm’s law still applies when it comes to calculating power dissipation. 

Below is a table of the different types of materials used and their typical power ratings. 

The importance of checking how much power a resistor dissipates?

Every resistor has a maximum power rating for a reason. Exceeding this value will cause the resistor to be damaged. 

This can lead to other problems in the circuit. 

Also, it will set you back on time and money. 

Calculating how much power the resistor will be subject to, and picking a resistor with the right maximum power rating, will save you a lot of stress in the long run.

The post Which resistor dissipates more power? appeared first on Electronic Guidebook.

You might know how frustrating it is when your mobile device is about to run out of battery and you have no way of charging it. 

A power bank solves this issue as you can recharge your mobile device on the go when you do not have access to a power outlet. 

But, what if your power bank is out of battery too? Can you charge a power bank with a solar panel? You can charge most standard power banks using solar panels. The ability to charge a power bank with a solar panel depends on how much power the solar panel can output which is determined by its power rating. There are different types of solar panels that come in different shapes, and sizes as well as power ratings. So, you will need to select a solar panel that is capable of supplying the voltage and current required to charge a standard power bank. 

Other factors that can affect charging the power bank with a solar panel are the amount of sunlight, angle of sunlight, surface area etc.

A deeper look at a solar panel and power bank

Taking an in-depth look at solar panels, and power banks will give you a better understanding on what type of solar panels can charge a power bank.

A note to be made is that, you get power banks that come embedded with a solar panel on them. These power banks have been tested with that particular solar panel to ensure that it can be charged efficiently. 

Our concern is whether you can use a standalone solar panel to charge a standalone power bank.

The Solar Panel

A solar panel has the ability to convert sunlight into electricity. It does this using a process known as the photovoltaic effect.

It is a great choice for powering homes, businesses, etc, as it is a form of clean renewable energy.

Solar panels come in a variety of ratings, shapes, and sizes.

The ratings of the solar panel are of great importance when creating a solar power system (which is a combination of a solar panel, charging module, and battery).

Solar panels have three ratings that need to be known which include ; Power, Voltage, and Current. 

These ratings are the maximum ratings that the solar panel is capable of generating. However, the solar panels ability to deliver these maximum ratings depends on the intensity of sunlight. 

Due to this, it is not effective to power electronics directly using a solar panel, as the power levels are not constant and vary with varying intensities of light. 

Instead, a solar panel is used to charge a rechargeable battery source which can then be used to power electronic devices. A charging module is used between the solar panel and battery to regulate the incoming power from the solar panel to make sure a constant voltage and current is delivered to the battery.

The Power Bank

Our mobile devices all have a limited amount of power which eventually runs out. This can be an issue if you are travelling and have no way charging your device.

A power bank was created as a solution to that problem. It essentially is a portable charger that can charge your mobile devices when there is no other means of charging them.

Like the solar panel, a power bank comes in a variety of shapes, sizes, current capacities, and ratings. 

The main specifications to look for when purchasing a power bank is its Output Voltage, Input Voltage, Output Current, and Capacity.

Output Voltage – This is the maximum voltage a power bank can output (you will need to match output voltage of your power bank to the input voltage of your mobile device)

Input Voltage – This is the input voltage required to charge the power bank.

Output Current – The maximum amount of current the power bank is capable of delivering 

Capacity – This is the maximum amount of charge the power bank can store when fully charged. The more charge that the power bank is capable of storing, the more times you will be able to charge your mobile devices. 

The conventional way of charging a power bank is to use a wall charger (which you use to charge your mobile device) via its input port.

Selecting a solar panel to charge a power bank

There might be times where you might have forgotten to charge your power bank before heading out on your long journey (or you might be on a journey where there isn’t any electricity available).

So, now your mobile device and power bank have no charge!

To avoid this situation from recurring again in the future, you have the option of using a solar panel in conjunction with the power bank to effectively create your own mobile solar power system.

As you saw above, a solar panel by itself cannot power electronics as its output power varies and requires a battery to store all that energy. 

A power bank can be used as that battery source and store the charge generated by the solar panel. The good thing is that the power bank has an internal charging module that can regulate power levels delivered to its battery via the solar panel.

Most mobile electronic devices (like smartphones), operate at 5 volts. Therefore, you will need a power bank that has an output voltage of 5 volts.

Due to this, a solar panel with a voltage rating of 5 volts will need to be chosen as well. 

A solar panel that is say 3.7 volts, will not have capability of charging a 5 volt power bank. So, the output voltage rating of a solar panel needs to match the input voltage rating of a power bank. 

What solar power rating is required to charge a power bank?

How effective a solar panel is when it comes to charging a power bank comes down to its power rating.

The maximum power rating (P) of a device is the product of its maximum voltage and maximum current (P = V x I). Its unit is watts.

An example would give you a better understanding. Below is a table of values of current and voltage for a solar panel and power bank (values are chosen randomly for this example).

The solar panel can charge the power bank, as it matches it in voltage values. However, it does not do it very effectively as it only delivers 2.5 watts of power, and the power rating of the power bank is 10 watts.

So, to be more effective, a solar panel with a higher output power rating will need to be selected for the power bank in this example.

Since the voltage of the solar panel needs to be 5 volts, its current will need to increase from 0.5 A to 2A in order to match the power banks power rating. 

Why not just charge a mobile device directly with a solar panel?

A mobile device needs a constant voltage and current to be charged effectively. Wall chargers can provide them with this constant power that will charge them at constant rate.

While it is not impossible to charge a mobile device directly with a solar panel, it isn’t very practical. This is because the solar panel will not be able to provide constant power all the time. 

So, a better option is to store the energy generated by the solar panel in a battery source which can then get delivered to a mobile device at a constant rate.

What else is needed to charge a power bank with a solar panel?

To connect the solar panel to the power bank, you will need the right type of cable which fits the input port of a power bank. 

There are many different types of input ports, but the most common of them being Micro-USB. This however, is slowly being replaced by Type-C ports. 

So, you will need to check what kind of port your power bank has, and accordingly wire the solar panel with a cable that matches that port. 

Do you need a charging module? No, you will not need a charging module as the power bank already has its own charging module. 

How long will it take to charge a power bank with a solar panel?

A power bank’s capacity is the maximum amount of charge it can store. The larger the capacity of a power bank the more charge it will be able to store, and vice versa. 

The unit for a power bank’s capacity is given in mAh (milli-amp-hours). 

To calculate how long it will take to charge a power bank to its maximum capacity, you will need to know its maH value, and the amount of current being supplied by the charger. 

So the time it will take = mAh / current.

For example if we have a power bank with a capacity of 1000 mAh, and a current of 1A is provided by the charger, it is going to take 1 hour (we need to use Amps values, so 1000mAh = 1Ah. We then divide 1Ah/1A to get 1 hour)

But, since we are using a solar panel to charge the power bank, another factor that will determine how long it will take to charge it, is how constant the level of current is being delivered by the solar panel.

The amount of current being delivered depends on the output current rating of the solar panel and the amount of sunlight that the solar panel is exposed to. The more sunlight, the greater the power output. 

So, the solar panel will need to be exposed to constant intensity of sunlight in order for the power bank to be charged at a known rate. 

Other factors that will affect how long a power bank will take to charge using a solar panel

So, how long a power bank will take to charge using a solar panel depends on two variables; the capacity of the battery, as well as the amount of sunlight the solar panel is exposed to.

But, there are other factors that come in to play as well:

• Placement of the solar panel – as well all know the sun does not stay stationary during the day. So, the placement of a solar panel to catch the most sunlight should be taken into consideration
• Whether the solar panel is stationary or not – You might be doing a hike and need to charge the power bank daily. You could place the solar panel on your backpack as you walk. However, this might not effectively capture the most amount of solar energy as you could be changing direction constantly. 
• Weather – Obviously the weather is a major factor. You won’t get the most out of the solar panel if the sun is not present on cloudy days. 

Where can you charge a power bank with a solar panel?

Charging a power bank with a solar panel requires one thing, sunlight. 

Below are some great places:

• In your car
• Outside your home
• Inside you home 
• Backpack as you walk
• Pretty much wherever you can find sunlight =D 

Advantages of charging a power bank with a solar panel?

One of the greatest advantages of charging a power bank using a solar panel is that it is great for our planet. Since we are generating electricity using the sun, it does not harm the environment in any way and is one of the most used ways of generating renewable energy. 

Another great selling point is that it is free! You will be saving on your electricity bills when you start charging your power bank with a solar panel. 

Also, since the sun shines on pretty much all parts of the earth (that I know of), you can charge your power bank, and therefore your mobile devices with a solar panel, no matter where you are!

Disadvantages of charging a power bank with a solar panel?

All things that come with advantages, will have its disadvantages, unfortunately

Here are some of the disadvantages of using a solar panel to charge your power bank:

• Only effective when sun at its brightest
• Cannot charge at night
• Weather dependent
• Charging times vary depending on factors like angle of sunlight, intensity of sunlight and weather.

How can you charge a power bank faster using a solar panel?

If you notice that it is taken a long time to charge your power bank with a solar panel, even when the sun is at its brightest, you have three options:

• Add another solar panel with the same rating in parallel. This will double the current output. Adding a third solar panel in parallel will triple the current output, and so on.
• Upgrade your solar panel to one which can deliver more current. 
• Get a bigger solar panel (one with greater surface area)

The post Can you charge a power bank with a solar panel? appeared first on Electronic Guidebook.