Car battery charger with MC78T12

Car battery charger with MC78T12 circuit

It is a very simple circuit that can be used to charge car batteries. In this circuit there are facilities to control the charging current and voltage.

The circuit is based on The MC78T12ABT IC. IC is just a 7812 in TO-3 package capable of 3A. The transformer T1 steps down the mains voltage and the diodes D1 and D2 does the work of rectification. The capacitor C1 and C2 is the filter acts as a decoupling capacitor.

The ground terminal of IC1 is raised to 2.1V with the diodes D3, D4 and D5. So the output of IC1 is regulated 14.1V (12 2.1). The battery is recharged through diode D6 D6.The blocks the reverse flow of current from the battery to the load circuit when the voltage is not available. Metro M1 shows the load current and M2 shows the load voltage.