This circuit will help you to control two devices with the help of a switch. If you "on" the first device then second device remain "off", and if you "on" the second [[wysiwyg_imageupload::]]device the first device will become "off". Therefore you can control both the devices with the help of single switch. The circuit is built around CD4017 which is a CMOS decade counter/ Divider. Used in many applications like binary counter/decoder, frequency division, divide by N counting, Alarm system etc. CD4017 is a 16 pin IC which includes 3 input- Clock, Reset and Clock inhibit. And 10 output Q0- Q9. Pin 16 is for power supply and pin 8 is used for ground. Read more to find out working of the circuit.