If belt tension is correct, then the next item to check is the alternator itself. You now have two choices - you can test the alternator yourself with a simple test using a voltmeter, or you can have the test performed by a professional. If you choose to do the test yourself, then you will need a DC voltmeter, or a multimeter. Such a unit can be purchased at most auto supply stores, hardware stores, department stores, home improvement stores, etc.
Modern cars come with complex electrical systems meaning that electrical diagnostics tools are needed in the repair and maintenance. That being said, the following are some of the most common auto diagnostic tools you will find in most auto electric repair shops. Digital motor checker - This is a vehicle diagnostic tool used in the maintenance of inbuilt electrical systems without any dismantling having to be done. This device helps in detecting problems that may result in tripping and therefore compromised electrics.
Of course, there are plenty of wiring problems an engine can experience and they can be very difficult to locate unless the mechanic is experienced. Analysing electrical problems requires using special equipment combined with mechanic expertise. Today's engines are extremely sophisticated combinations of electronics, electrical wiring, and moving parts and seem like they are half-computer and half-mechanical.
Starter: starting the car was a sweat-breaking business before the starter. A procedure by it's own, where you had to be fairly skilled. Cranking the car was done with a cranking rod. The driver would put it into place, use all the strength available, crank the engine and if he's lucky the engine would start after a few turns. If not, he was in for another lesson in body-building. Aside that, when the engine started the driver had to let loose of the rod in time or else he would get a knock in the face. Every time you put the key into the ignition, remember this and enjoy it as a privilege.