hi all dear friends o i m doing a mini project in electronics on digital tachometer circuit as in attached files also it could be find out ongoogle ebook search as electronics for u projects vol 21 digital tachometer circuit. i want know how to design it's circuit elements each and every parts from register to leds, etc. i.e step by step procedure for it's designing or any books relating to that i.e for any circuit designing . i m in real hurry to get this so please provide me as early as possible. i m facing uploading problem here so it may happen that circuit may not be uploaded so i m sorry about this. thank u very much.