Can VPNs see my passwords?

So this is something that a lot of us were contemplating. Are VPNs like 'ZenMate' or 'Psiphon' safe to use? We are sending data to their servers first, which is then routed to destination server. So can this intermediate VPN server see credentials like my username and password?

The answer is:
 - They cannot see your password if the website you are accessing is 'secure'.
 - They may be able to see your credentials if it is an 'unsecure' website.

Secure Websites

These are websites like Google and Facebook that have a secure protocol for exchanging data between our web browser and their main servers.

So if you are using a VPN, the data to be sent to Google servers will be encrypted by Google, your VPN encrypts that encrypted data again(thus, adding a second layer of encryption) and sends it to the VPN server which de-crypts it.

Now, even if your VPN server tries to read the information in the packet, it cannot, because it still has that first layer of encryption that only the Google server can de-crypt. So your username and password are safe and encrypted.

To know if a website is secure or not you can check the lock icon on the extreme left of the address bar of your web browser. Click on it for more information about the certification as shown.

Also the website will have 'https(Hyper Text Transfer Protocol - Secure)' as a prefix in green.

Thus it is safe to sign in to gmail.com using my username and password via any VPN.

Unsecure Websites

These websites do not encrypt their data while sending it to their servers. So if you are using a VPN, the VPN will encrypt the data to add one layer of protection, the VPN server will decrypt it and if the VPN server tries to sniff what data is contained in the packets, it may be able to see your credentials like username and password!

This is what an unsecure website looks like:

The is no 'https' prefix and it says that the connection is not encrypted. So it is not safe to sign in using a username and password to gocomics.com via a VPN.

So always make sure the websites that require login are secure for accessing via a VPN!

How to solve 'Battery not recognized' error.

Recently one of my friends changed his laptop battery. He has a Dell Inspiron 15R just like mine.
However he wanted a battery with a better capacity.

Now there are batteries available with different capacities like 48WHr, 60 WHr, 95 WHr and so on. His original battery was 48 WHr. And a battery of better capacity wasn't available for Inspiron 15R. So he went for a Dell Latitude laptop battery which fits into his Inspiron and is 60 WHr. The batter is original from Dell themselves, but since it not made for Inspiron, it gives this 'Battery not recognized' error sometimes. Otherwise whenever it detected it, everything was smooth and the laptop charged the battery.

If you laptop does not recognize the battery then it simply does not charge it. Though it can use it and will work till it gets fully discharged. You can then switch off your laptop and charge it in the switched off state. But this is impractical and tedious.

We broke our heads over this for a long time. Literally scoured the internet. But since the battery was giving a nice capacity which lasted 4 hours, we were reluctant on returning it. Finally found the solution. This does not make the error go away permanently and you will still get it if you don't follow the steps as mentioned below.

Solution 1: Starting without AC adapter

1) Don't plug in your AC adapter in the laptop charging port and just press the power key. Your laptop will start and give this error 90% of the times.

2) Press the power key again. Laptop will switch off.

3) Wait for 2-3 seconds and switch it on again. Miraculously you will not get the error and laptop will boot up and everything will be normal.

Solution 2: Starting with AC adapter

1) Plug in your AC adapter in the wall socket.

2) This is major step now and will take some getting used to. Plug in the DC jack in the laptop port and immediately press the power key within 3 seconds. Only then you won't get the error.

I found this solution on my own, it seems to work for us and may not work for some people. If it doesn't then try out the solutions given on these links.

Dell Community Forum
Raymond Blog

Cheers! :)

How are electronic gadgets made slimmer and compact? OR How are more features added without increasing gadget size?

Edit: 4 Feb 2016 - I got a lot of feedback about this post and many told me it looks rushed. My answer is, that is exactly how I want it to be. If I go into the core technicalities, it will become tiresome for my blog followers from a field other than Electronics. I however, really appreciate the feedback and have added some links to deeper information at the end. Thank you everyone!   

About 80% of what is written here springs from a subject, 'IC Technology' taught in my 7th Sem of Engineering.
--

"How do they reduce the thickness of our smart-phones and make the circuit size smaller?" 

"How come they are offering 128GB of storage in that small micro-SD memory card!?"

I get these questions a lot!

To all of you curious people, I now consider myself qualified enough to answer this and this itself is my career choice! :)
The answer is : Very Large Scale Integration(VLSI) and Moore's Law and we will further discuss it in this post. Hope you enjoy this crash course! :)

VLSI

I am taking you to Semester 3 and 5 of my Engineering. What I am about to talk on is the most basic building block of any circuit(memory cards, processors etc.), that is, a 'Transistor'.
Bottom line: Smaller the transistor, more dense is the circuit or more features can be made available in previous integrated circuit, keeping size same.

This is how more space is made available in memory card without increasing its size! Smaller transistors occupy less space and hence more transistors are fitted to give more data storage capacity.

Details:
Lets say you have a transistor. Specifically a type of transistor called as a MOSFET(Metal-Oxide Semiconductor Field Effect Transistor). MOSFET sounds pretty complex but, for our present scope, lets say it is as simple as pushing a button to switch ON/OFF a light.

Basic diagram of all MOSFETs at the core level: Made using a material called Silicon, its other types and its oxides. 

The ones we use for our experiments in college, have dimensions in centimeters like these:

In the transistor package featured above, a billion transistors can be fitted, in place of just one. However, the package is made purposely bigger, just so that we can handle it. Otherwise even this bigger transistor has a smaller circuit inside, like shown in the diagram. 

To explain the scale we are talking about, in size reduction using VLSI, Apple's A8 processor introduced in the iPhone 6 has a size of 1.05cm x 0.85cm and has 2 Billion transistors. That's VLSI. Each transistor on this chip has dimensions in nano-meters.

This is how an extremely small size transistor fabricated at the nano-meter scale looks like:

This is a special type of transistor, called a FinFET.

They have special laboratories to fabricate components on the nano-scale. They are called nano Fabrication Laboratories or FabLabs. Here is a view of one:

Companies like IBM and Intel came up with transistors which are even smaller(9 nm). They use something called as Carbon Nano-Tubes(CNT) Technology.

Carbon allotropes like Graphene (a single layer sheet of carbon with a thickness of 1 atom) are unleashing a completely new era of electronics! CNT is made by rolling up this Graphene sheet. We will soon have (and already have) technologies like fold-able and roll-able screens, transparent electronic gadgets and micro-circuits which can be extremely useful in bio-medical and wireless applications!

Processors and gadgets's circuits are thus becoming smaller, energy efficient and even more powerful! Now-a-days Systems-on-Chip or SoC are gaining more popularity. The processors in our phones are not just processors or CPU, they are an SoC. SoC means they can do the mathematical processing, as well as the graphical processing and have on-chip memory which makes them blazing fast!

Example: Apple iPhone SoCs

Moore's Law

The co-founder of Intel and Fairchild Semiconductor, Gordon E. Moore postulated that the number of transistors in a dense integrated circuit will double every two years. This postulate became such a common phenomenon that we now call it a law!

For example: A 4 TB external HDD of 2014 is of same size/smaller than 2 TB HDD of 2012. See how the transistors doubled in the same space! :)

Brace yourselves. 'The Future' is no longer the future..its already happened! =) 

Links to more info:
Semiconductor device fabrication - Wikipedia
VLSI Fabrication Technologies - Emanuele Baravelli
VLSI Design, Fabrication steps and layout - Shaahin Hessabi
IC Fabrication Techniques - circuitstoday.com

Tukzer 10000 mAh Power Bank Comprehensive Review

After a lot of research and a budget of around 1000 INR, I decided to buy the Tukzer 10000 mAh power bank. A decision I do not regret at all!

If you want to see the result of that research, check out this post - Which are the best quality, reliable and high output Power Banks and Chargers for USB devices?

This is by far the best power bank for the price of 1.1K INR. I got this in Lightning Deal on amazon.in

Most important points:

• Micro-USB cable included is of a high quality and ensures maximum charging speed.
• It gives a charging current of 1.5A from the 'Tablet' output port and 1A from the 'Phone' output port.
• It takes about 9 hours to fully charge when drained.
• It charges my 3100 mAh Galaxy Note II battery 3 times.

Pros:

1) It is extremely light (about 300g) and compact for 10,000 mAh.

2) High Quality Li-Po batteries ensure maximum efficiency.

2) Overcharging protection circuitry.

3) Shake to see how much charge left on LED indication feature works great!

Cons:

1) Should have had a power ON/OFF button.

2) Does not support pass-through charging, that is, does not charge phone if power-bank is charging.

Verdict:

If you need a stylish power bank of high capacity, high efficiency, light weight and safe, then go for it without second thought! Great bang for the buck!

Which are the best quality, reliable and high output Power Banks and Chargers for USB devices? (India)

I get this question a lot and I recently answered it on Quora too. Here is a more detailed answer with brands chosen among the ocean of other Chinese brands based on their reviews and personal experiences of my friends.

The brands listed here manufacture products for both Android and Apple devices. So happy reading!

Power Banks:

More details on how to choose one and what the 'mAh' rating of power banks means is given on my other post here:
Powerbanks: Which one to buy? What is mAh?

The best Power Banks to my knowledge as of Jan 2016 are:

1) Tukzer - 5200/10000 mAh

Tukzer is possibly the best looking and the best performer among all. It is lightweight and has high Quality Li-Po batteries. Shake the power bank to see the charge level!
You can find a comprehensive review on this one here: Tukzer 10000 mAh Power Bank Review 

2) TP-Link TL-PB - 10400 mAh

Comes with a pouch and in-built flashlight. Slightly heavy. This may not give the full backup capacity as promised, based on some reviews and is 70-80% efficient. 

3) Sony 4700/6100/10000 mAh

Possibly the longest surviving power banks are made by Sony. But they are very expensive.

4) Xiaomi 5600/10400/16000 mAh

Xiaomi is s very well known company for power banks and some of my friends are still using their's since two years. However, these are rarely available as of 2016 in India.

Wall chargers or USB power hubs:

A charger with a 2 Ampere rating will charge your device the fastest. Do not worry, a high current charger will not damage your battery. Your phone can take only a limited amount of current which is decided by the manufacturer. So if it is not manufactured to sink current above 1.5A, it will take only 1.5A even if you connect a 2A charger.

The best wall charger or USB power hub manufacturers for charging your devices as of Jan 2016 would be:

1) Anker (Qualcomm Quick Charge 2.0 18W)

Be careful, online shopping sites are plagued with first-copy duplicates of Samsung and Apple models. Buy from reliable sources.
2) Samsung (2A) 

3) Apple (2.4A)

4) Sony (2A)

5) Nextech (2.4A)

6) QuantumZero (2A)

7) Tukzer (Power Hub 2A+2A+1A+1A)

Charging/data cables:

With a good quality charging brick/hub, you cannot compromise on the quality of the charging cables. Otherwise if the cable offers more resistance or is not made of a good quality material like copper, it will reduce charging speed to a significant extent.

The best charging/data micro-USB cables:

1) Bandridge - 100% Copper cable

2) Tukzer

3) Rock