The project described here can be used to switch ON and OFF the electronic device. The time period for which the device remains ON is same as the time [[wysiwyg_imageupload::]]period for which it will remain OFF. We can use it in many applications like controlling the activity of mosquito repellents which use toxic material to generate poisonous vapor to keep mosquitoes away from the room. Continuous release of this vapor may harm our brain and long exposure to these toxic vapors may cause neurological, asthmatic or skin related problems.About the circuit: The circuit is created using NAND gate along with a relay, transisto BC547 and few resistances. NAND Gate is created by applying NOT operation to an AND gate. Hence, the outputs of this gate are opposite to that of AND gate when the inputs are kept same.