Mileage=50km/ltr

so in 1 ltr distance travelled = 50 km=50000 mtrs

radius of wheel=70 cm

circumference=2(pi)*70=439.82 cm=.43982 mtrs

so number of wheel turns=50000/.43982=113682

so fuel burned in one cycle=1/113682=0.0000087964 ltrs

Build A One Transistor FM Radio

Introduction
AM radio circuits and kits abound. Some work quite well. But, look around and you will find virtually no FM radio kits.

Make Your Own Low-Power AM Radio Transmitter

Objective
The goal of this project is to build a simple AM radio transmitter and to test its broadcast range with a radio receiver.
Introduction
Electromagnetic (EM) radiation is pretty much all around us. For example, light is electromagnetic radiation and so are x-rays.

Tips to Extend Your Lithium Battery Life

Lithium batteries seem to be everywhere these days. We can find them in our cellphones, laptops, portable media players and etc. We all want to make our batteries last as long as possible, but some well intentioned advice from friends, could be harming your Lithium battery’s life span.
1. Battery Memory - When I first got my new cellphone, my friend recommended to fully drain the battery before recharging it. His reasoning was connected to the idea of battery memory.

Phone Broadcaster

Phone Broadcaster

 Click here for the circuit diagram

Here is a simple yet very useful circuit which can be used to eavesdrop on a telephone conversation. The circuit can also be used as a wireless telephone amplifier. One important feature of this circuit is that the circuit derives its power directly from the active telephone lines, and thus avoids use of any external battery or other power supplies.