Do you know that almost every house has a free electricity source?�Yes that is true!� No bills !

This short post will show you how to find that free secret source and make use of it. But first let me ask you this question: Do you know how a telephone works? If no, please click�here�for more details.

In summary, telephone lines at homes connect to the telephone network using two wires called�Tip�and�ring. Usually the tip is green colored and the red is ring and these wires�are connected to the telephone company and used� for all the communication between� users. They have limited bandwidth and carry� a permanent48VDC�and temporary�40VAC to 70VAC�that only occurs when the telephone line rings. Maximum electric current that can be drawn from the wires is almost 50mA,� and both the DC/AC voltages are supplied by the telephone company using special batteries and AC sources. So the DC voltage is available at home 24/7 and AC is only there when your phone rings!

With this in mind, why don’t we use this 48VDC of the telephone network at homes to operate some simple electronic devices?� So can we consider this telephone line as a “free” hidden electricity source? Of course we can! so any house with a telephone line can be used as a free electricity source with some limitations on voltage and current. Remember current is limited to around 50mA and voltage to 48VDC. So now let’s� build a� simple circuit that� converts or limits this voltage to say� 5VDC and use it to power a simple LED lamp. Keep in mind that if a telephone rings then a 40-70VAC will occur on the line, so we must protect our DC circuit and convert this AC into DC. Let’s watch this tutorial:

I think the video is clear, it shows� a simple circuit which consists of two main components: a�bridge rectifier�and a�voltage regulator�interfaced with a telephone line. These two components will make use of both the AC & DC voltages and power� a LED lamp. Circuit schematic:

Here are some tips:

1. 48VDC� can be changed to a lower DC voltage according to your design using� any voltage regulator . You can use this�link�to find out more


2. AC voltage will be there when telephone rings, so we should use a bridge rectifier to convert this AC to DC. To buy a rectifier click�here
   
   


3. Safety first!

You can download the full circuit from here:�FREE-Hidden-Electricity Circuit�and if you want to control devices at home remotely using telephone line then try thislink.

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Two weeks ago I was chatting with a friend of mine about traveling and where to spend the holiday. Suddenly,� he told me: Well Mr. Electronics, since you’re bothering us with your electronic topics & posts every time on your blog , can I ask you this trivial question?

I told him: ” Yes please!” and seriously I was worried that he’s gonna fire a tough question on me. So here’s his question:

A while ago I was traveling to�Egypt, and I used to carry my own hair dryer during any trip. The dryer was rated @220V/60Hz, and in Egypt electricity is220V/50Hz,� at first glance, it seems to be fine, both Egypt electricity and my hair dryer were compatible except for frequency, however, when I plugged in my dryer in the socket it was on for like a couple of seconds and then was burned out! In fact, this story happened again� and the same scenario repeated, same hair dryer brand and same country, so what could be the reason behind this strange dryer? Is it frequency? or what?

Hmm..Sounds interesting question!

So let’s see why did this happen, and how to avoid it.

Basically, there two electrical systems in the world:

1.� 220-250V/50Hz

2. 100-127V/60Hz

In some cases, like in�Saudi Arabia,� we have 220V/60Hz and not 50Hz as should be. But� before we dig more into details, why do not we have one electric system? Why not 220V only? or 110V? To be honest, there is no technical reason behind this,� and in my opinion it could be some political issues between “British” and “US”.

Anyhow, so for each system there are two main properties that you should consider before buying any electrical device at any country. These are:�Voltage�andFrequency.

See fig.1 below:

So the above signals demonstrate the “amplitude” and “time” characteristics of any electrical system you can find at electrical sockets at home. The frequency is basically how many times the signal repeats itself per second. In other words,� normal light bulbs at home should turn on and off 60 times per second in a 60Hz net.! but since our eyes can’t detect this high on/off� rate� because maximum normal eye detect 25Hz so anything grater than 25Hz appears like a constant signal. Similarly, any device like a motor for example should rotate according to this frequency.

Back to our hair dryer example, the dryer has a motor inside which was rated at 60Hz meaning it should rotate 60 times/second so if it was used in a�50Hz�network “Like Egypt” then simply the motor will rotate at slower speed “50 in this case”. In conclusion, the frequency will not damage the hair dryer if you’re using a 60Hz rated dryer in a 50Hz network.

So what might damage it?

It ’s Voltage! Looking back at the graph, it’s clear that the voltage amplitude has a range with a minimum and maximum.� Let’s assume our dryer was rated at 220V/60Hz, and say in Egypt the network supplies 240V/50Hz, in this case the dryer will� rotate at a slower speed and receive 20V extra! which more than its rating of 220V, so it will simply rotate for a couple of seconds and then you start smelling the nice perfume of your dead hair dryer motor. This happens because the voltage of the dryer is 220V and the electric network gives 240V.

So what’s the solution?

My first advice would be: Read the voltage and current rating� as well as frequency rating of any device before you buy it.� Usually you’ll find these ratings on the name plate. You will also find that devices� from different manufacturers� have different ratings, for example: a hair dryer might be rated at 110V/60Hz, 115V/60Hz, 120V/60Hz or even 127V! so pick up the 127V to be on the safe side. For electric current rating, or power rating, try to buy the minimum possible rating as this would save your power consumption and save your electric bill. Read my�old post�to know more about current rating. Finally, For frequency, usually it’s standard and you won’t find different variations and for motor applications this won’t affect your operation if your going from 60Hz to 50Hz. But don’t do the opposite! Don’t use a device rated at 50Hz in a 60Hz network!

My second advice is to use a voltage regulator or commonly known as�AC Voltage Stabilizer�to maintain the voltage level in your network in case of fluctuations.

In summary, watch out for voltage rating and frequency and try to buy low power “low Watt” equipments.

Finally, I wish you nice holidays and safe vacations!

Does the picture on the right look familiar to you? Of course yes! It’s a Nokia Mobile�Li-Ion�Battery.

Recently, I noticed that my mobile phone battery is discharging at a faster rate than before. I’m quite sure many of you have faced this before, so I decided to dig more into this topic to know what could be the reason behind this fast discharge, and how to get rid of it. I will also provide you with a simple circuit that can be used to charge any Lithium Ion battery which can be constructed easily.

Surfing through the web,� you will find some general tips to save the more power of your battery, and I think most of� us are familiar with, so here are some of these tips:

1. Turn unnecessary applications or modules off. Modules like : GPS, Blue-tooth, Wifi, screen brightness, etc. consume� a lot of power as well as applications.
   
   


2. Make sure to update the mobile firmware regularly, usually manufactures add new features to reduce power consumption.


3. Use batteries at rated operating temperatures. You can refer to my�old post�to know more about this subject.
   
   


4. Charge the battery fully and make sure to discharge it completely.


5. Clean the battery contacts on the battery, and inside� phone. Over time, contacts may accumulate dirt.


6. Stop searching for a signal. When you are in an area with poor or no signal, your phone will constantly look for a better connection, and will use up all your power. The best way to ensure longer battery life is to make sure you have a great signal where you use your phone.
   
   

To me, the above list sounds trivial and I assume many people knew it before, but here’s something new which can be applied to gain more power out of battery:

1. If you are using Nokia, then use Nokia’s Power Saver option�– Nokia gives you a default screen saver in your mobile phone which switches on your backlight to show its features etc. This is actually not needed to anyone, and it also eats up your battery without any benefit for you. Just turn this Off by activating Power Saver option On and set it with a minimum time so that the backlight turns off and your screen shows just the Date and Time.


2. Use a single mode of network�– There is an option of GSM, UTMS or Dual mode of networking when you go to Tools > Settings > Network settings. You should select any one network, not the dual-mode of networking, as you are already using a GSM SIM and need just that network to connect. The other modes are battery eaters, as many suggest.


3. Your favorite theme? Have it in your phone memory�– Only if there is some space in it. A small theme that you are using in your mobile, would be there On for all the time. And for this, the mobile system has to be connected to the memory card and receiving the info about it. Why not keep it in your phone memory and keep the 2 systems(Memory card and phone system) not connected? This would save some battery for sure.


4. Never charge your battery for more than 14 hours


5. Nickel-Cadmium (NiCad) batteries suffer from an affliction known as the�memory effect. The battery will only charge to the level of which the battery was last discharged due to an accumulation of gas bubbles on the cell plates. If a battery is discharged to 30% and then recharged, the battery will only charge to 30% of its capacity and thus shrinking the battery’s “gas tank.” So the best approach to overcome this problem is by draining the battery until your portable phone shuts off, and then recharging it.


6. If your battery used to last�8 hours�and now only lasts 2 hours, it could be memory effect or just time for a new battery. NiCad batteries last approximately 700 charge/discharge cycles, or about one and a half years on average. However, NiMh batteries will normally