this paper introduces a kind of the rectifier circuit, adjustable constant current charging circuit, detecting voltage circuit, display circuit and power circuit of six parts of constant current source charger design scheme. The charger using op-amp composition adjustable constant current charge, constant current source circuit to avoid the constant voltage charging and lack of such as output voltage will vary with load, using a 555 timer consists of oscillator and general TL082 J - FET dual operational amplifier, compared with 3V voltage reference test voltage circuit to realize full automatic disconnection functions.