SD Card Reader

What is SD Card Reader?

In simple words an SD card reader is a data input device. This has the ability to read the files stored in a data storage medium which is in the shape of a card.

Any modern card reader is able to read several types of plastic cards. These cards may be embedded with many different things such as:

Understanding SD Card Reader

What is SD Card Reader in Laptop

Apart from reading, most of the card readers today also allow writing capability, and collectively with the memory card, these card readers can perform even as a pen drive.

If you are interested to know more about the SD card readers, which is a specific type of card reader that is extensively used today, this is perhaps the best article to read for that matter.

An SD card reader is also alternatively known as a Secure Digital card reader, a media card reader, or simply as a card reader.

Irrespective of its name, it typically signifies the hardware device that helps in reading data from or writing data on a memory card.

Ideally, the SD card readers may come in different forms.

There may be some that have only one card slot in them while a few of these card readers may support reading from or writing on multiple cards through the different slots in them.

An SD memory card reader refers to the complex device that allows accessing the stored data in a variety of memory card in its different slots which can be any of the following:

However, all SD card readers may not be compatible with all types of cards.

The card readers are most useful for those users who want to download or transfer information or data from an expanded storage or memory from a digital camera or a smartphone.

The external SD card readers, in particular, are usually a basic device and are very compact in design.

However, all SD card readers do not need to be always an external device.

An SD card reader can be either an external accessory or can be built into your laptop or a larger device including some printers and computers.

However, irrespective of the build, the SD card readers will act as a successful medium to copy or transfer files or data from one device to another.

Still, there is one significant drawback of the SD card readers that are built in comparison to those that are external.

It is that the memory cards of different sizes may not be read by the built-in SD card readers.

Most laptops today come with an SD card reader built in them for convenient sharing of information and data stored on an SD card.

Therefore, your laptop should come with one as well.

You can see it directly in one of the sides of the casing. However, if you do not, then you can check it out in the device list of your computer or contact the manufacturer directly for the necessary assistance.

Normally, the SD is light in weight and small in size.

Some of the SD card readers even resemble standard USB flash drives which makes it quite easy to carry it around.

Moreover, the functioning of the SD card readers is also quite similar to that of the USB flash drives.

However, there is only one specific difference between an SD card reader and a USB drive, which is that the former can read a wide range of flash memory cards but the latter can read only the floppy disks.

However, all types of SD card readers may not produce similar results or performance.

The primary reason behind such differences is the variation in their speeds.

The speed of the SD card readers refers to the time taken by it for the information and data to transfer from the memory card to the other device that needs to be accessed.

Some of the SD card readers may not read the data as quickly as others from the memory cards.

Another important reason for the difference in the performance of different SD card readers is that some of them may not be able to interpret a few specific types of memory cards at all.

This is one significant reason that the users who typically use many different sizes of SD cards normally use a multi SD card reader.

These specific types of SD card reader comes with multiple slots in them that allows using one device only to read different types of Secure Digital cards.

File Formatting

Depending on the type of the card reader, and on the device on which it is built in, it may even allow formatting a particular file system other than any form of File Allocation Table or FAT format such as FAT 16, FAT 32, or exFAT to NTFS or New Technology File System.

Usually, the SD card readers support different files systems of all major types of operating systems such as:

This is a useful feature because smartphones, cameras, and other similar devices format files typically in FAT only.

Features to Look for

Ideally, if you want to make a choice between a given variety of external SD card readers to use in your laptop, there are a few specific features that you should look at and compare it with the type of memory card you wish to use.

Ideally, the features of the memory card should be compatible with the SD card reader and vice versa.

This will assure that it is quite good in performance and is worth investing in.

Therefore, the factors that you should take into consideration are:

Also, check in your laptop for additional ports.

If your laptop comes with fewer ports on its sides, as is the case with most modern laptops, it may be wise to use an additional card reader hub with spare USB sockets so that you can use an SD card reader with your computer.

How to Use It?

You do not have to be very tech savvy to use an SD card reader.

The process is very simple and you will not need to have any prior training or possess an extraordinary set of skills to use it.

If you are using an external SD card reader, here are the simple steps to follow:

However, you should keep in mind that you will be able to access the SD card only when it is inserted properly into the SD card reader, and the card reader, in turn, is also connected properly to the computer.

Though the most ordinary way to connect an SD card reader to a desktop or a laptop computer system or any other device for that matter is through a USB plug, you may also use FireWire or parallel printer ports.

The cord used to connect one device to another however may or may not be removable.

And, if your laptop computer comes with an SD card reader built in it, you will simply have to insert the SD card into the appropriate slot, properly once again, to access the data or files stored in the card.

In this case, however, you should keep in mind that the specific model of your laptop may have an SD card reader that may need the card to be inserted upside down.

Symptoms and Troubleshooting

The SD card reader may not start working instantly as desired. Sometimes the card reader may not be able to read the SD card in the first place.

However, there is nothing to fret because there are some easy ways to resolve such an issue with the SD card reader or the SD card as well.


First, you will need to find the cause of malfunction and for that you will need to know the specific symptoms for it and then follow the steps for rectifying the error.

Here are some of the specific symptoms of an SD card reader not functioning properly:

Now that you know the symptoms, it is time to try and find out the cause of the issue.


The probable cause of such issues with the SD card reader could be several and some of the most common ones are:

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Now that you know the causes, it will be easy to follow the troubleshooting steps.


Depending on the cause of the issue, one or a couple of these following solutions may resolve the problem with the SD card reader:

If the issue persists even after following these steps, there may be something seriously wrong in your computer system that is over and above basic troubleshooting tips.

In such a situation, you will need to contact the technical support of the manufacturer of your computer system for further help.

How Does It Work?

It is true that you simply insert the SD card in the appropriate slot and it starts working but that does not explain how the card reader works exactly.

In order to understand the working process of the SD card readers that most of the modern laptops come equipped with, you will need to go a bit deeper into the matter and understand its design aspects.

Typically, these card readers, in general, are designed in such a way that they can read different card formats such as T-Flash, Memory Stick, MMC or MultiMediaCard and others.

It is for this reason the card readers usually have several slots in them and, as a result, are often referred to as Multi Slot Card Readers.

Here are the features of an SD card reader that helps in its working process.

The Outer Casing and Printed Circuit Board Assembly

The outer casing of the SD card readers is usually made from plastic in order to reduce the cost.

The USB connector emerges from it which needs to be fixed to the slot correctly.

Inside this, there is the Printed Circuit Board Assembly or PCBA. There is a slot in it that holds the SD card.

The power is supplied by the USB connector and is sufficient for the card reader to function even if all of the card slots in it are used at the same time.

The USB connector also performs another function apart from supplying the necessary power to the unit. It helps in carrying data as well.

The version of the USB or Universal Serial Bus interface will however determine the rate of data exchange.

For example, according to the norm, a USB v2.0 can operate at a data transfer rate of up to 480 Mbps.

The Integrated Circuit

Next, it is the IC or the Integrated Circuit that plays a major role in the working process of the SD card reader.

This IC is usually covered by the rear casing of the SD card reader. Ideally, the IC is considered to be the heart of the SD card reader.

The IC usually comes with reader chips with pins, such as a 28-pin card reader chip, as well as an internal ROM or Read Only Memory to hold the required firmware for data exchange.

This is usually burnt into the IC at the time of manufacturing.

A microcontroller based IC will also come with a crystal oscillator to clock it and the pin arrangements will be very immaculate to facilitate easy placement on the Printed Circuit Board.

However, if it is a low-quality and quite cheap card reader, it may come with a Chip On Board or COB IC and not a Packaged or Surface Mount IC.

The performance of these types of card readers may vary significantly while reading cards or while responding to the locked cards.

Top Casing

Now, take a look at the top casing of the SD card slot.

This serves several purposes. One of the major functions of it is to ensure that the card is inserted properly into the slot.

This can be identified with the faint ‘click’ sound when the card is inserted properly. This click sound is produced by the somewhat curled wing.

This curling also has an added functionality, which is to ensure that the card does not get scratched or damaged when it is inserted into the card reader.

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In addition to that, the casing of the SD card reader also helps significantly while responding to the card locking mechanism.

There is a plastic structure below the top casing that comes loaded with several pins both on the upper and lower sides of it.

These pins are usually curved which helps in offering leaf spring action.

The pins on the upper side, as said earlier, allow easy gripping of the memory card when it is inserted into the slot.

And, the pins on the lower side of the structure secure the connections with the pins of the card that allows data transfer.

The pins on the upper and lower sides are typically placed in an alternate manner on the structure in order to prevent accidental touching of each other.

Since these pins will not come into contact with each other in normal conditions there will be no chance of any false signals signifying that a card has been inserted while it is not.

Usually, all SD card readers come with a 9-pin interface through which the transfer of data takes place.

These pins are located a bit deep inside the casing of the SD card reader which once again prevents unintended shorting of any two pins.

Protected Mode Detection

More often than not, an SD card may come with a lock switch.

When this switch is engaged, any further modification of the data stored inside it is not possible.

This means that ideally nothing can be written or read in it.

However, the SD card reader itself should be able to detect this locked or protection mode of the SD card.

However, how better the card reader will understand the locking feature will typically depend on the card itself.

Therefore, it should be of good quality so that the data stored in it remains safe when the switch is ‘On.’

This is because the lock switch of the card is not connected directly or in any way with the card reader.

However, when these are unlocked, the card is connected by the upper metallic casing of the reader.

This casing has internal protrudes that facilitate connections between the switches.

If there are two switches, then the first switch should be elevated while the second one should be connected to the metallic casing to allow modifying the content in the SD card as soon as it is inserted.

This means that the lock will pull up one switch so that there is a connection with the metallic casing which is connected to the second switch.

This, in turn, enables read and write operations.

On the other hand, when the lock is disabled, the first switch is placed close to the lock switch.

This does not allow making any connection with the metal casing.

The data in the card is therefore read and write protected and cannot be changed.


Ideally, there are only three major types of card readers that are typically categorized on the basis of their types and quantity.

These are:

Do You Need an SD Card Reader?

There is no way in which you can connect an SD card to your laptop computer directly. Period.

Therefore, if you want to access the data or files stored in your SD card, you will need an SD card reader for sure.

In theory, you should use an SD card reader in your laptop.

This is primarily because the read and write speeds of such types of cards that are connected through a card reader are much faster in comparison to those cards that are connected through the card slot of a physical device that uses such cards.

Also, you will get reliable performance from the SD card reader. There are several slots in the card reader that will support different card sizes.

The most significant advantage of using an SD card reader is that you can connect the card directly to your laptop without needing to attach any external device to it.

This in turn, will simplify using, organizing and storing the cards.

Therefore, if your laptop does not come with an SD card reader, you are missing out a lot.

It is extremely necessary to have an SD card reader in a laptop.

However, in the end, it can be said that the SD card reader can prove to be very useful but all of them are not created equal to fit in a laptop.

There can be a huge variance in the performance if you do not choose the right one for your laptop.

Therefore, you are requested to do a little bit of research on the specs and compatibility before you eventually make your choice to get a high return in the form of performance and value in return for your investment.


Well, with all that said and explained in this article, it must be very clear to you now that you will be better off using an SD card reader in your laptop for transferring data and files easily.

With the knowledge you have gained through this article, making the right choice will not be difficult for you anymore.