It is a simple car voltage stabilizer that connected directly to a car battery.The function is to stabilize or filter an AC voltage from the alternator to get a clean DC voltage. A clean DC voltage is required for electronics equipment to operates in optimum condition. The alternator voltage output is regulated and still has AC noise which will cause a humming noise to a power amplifier. This circuit will filter both low frequency noise and high frequency noise. The lower value capasitor will filter high frequency noise while higher value capasitor will filter low frequency noise.