Have you ever been caught in a situation where your phone battery is flat and you need to make an urgent call but there is no power to charge your phone? It can be frustrating and demoralizing, isn’t it? Well, that is for those that are not aware of a simple solution. Like they always say, knowledge is power. If you are not informed, then you are deformed.
Your phone line is a free source of power and it is lying fallow. You can use it to power your phone and other small electronic devices. However, this solution is for emergency situations only. So, it is not advisable to do it for long or to make it a habit.
Do you know why corded phones do not need to be plugged into any electrical socket before they are used? It is because they get all the power they require from the phone line. Your telephone company transmits power to your house through a couple of dedicated wires that are connected to your telephone jack.
Phone companies usually have their own backup power system so whether there is power or not, your phone line will be powered. This is what you will cash in on when there is no power.
Step-1: Check your voltage with a multimeter
Since voltage sent to phone lines actually vary slightly, it is advisable to quantify yours with a multimeter. Open your phone cord and separate the two internal wires. One is usually green while the other is usually red. Remove the rubber insulators at the tail ends of both wires.
Plug the red wire into your phone jack and measure the output. If you get anything between 51.5 volt and 53 volt, then you are good to go. But most phones require only about 5 volt to charge. So, you need a voltage regulator to bring the voltage down to exactly what your phone needs.
Step 2 – Construct a regulator
You need to get a 5V voltage regulator and a USB connector cable with a female end. Carefully connect the red wire to the first pin on the regulator and connect the green wire to the second pin. Remember that the USB cable also has a black wire and a red wire. Connect the black wire to the second pin and the red wire to the third pin. Ensure that you bend each regulator from the others to prevent accidental contact.
To protect your circuit from reverse polarity problems that may occur when your phone rings, you can add a diode between the phone line’s red wire and the first pin.
Step 3 – Plug your phone cord into a phone jack
Finally, just plug your phone cord into a phone jack and plug your phone charging cable into the female end of the USB cable that you worked on. You can now connect your phone to charge it for some minutes. Within 10 minutes your phone should be charged enough to make calls.