What are the circuits of the battery repair instrument?

The AC voltage of 1 220V is converted to about 30V. After bridge rectification and filtering, one path is supplied to a multivibrator with adjustable duty ratio, which is composed of 78 12 voltage-stabilized output driving 555 time base circuit. The output rectangular square wave drives two electronic switches IRF630N to form pulse charging for the charged battery. Relay and diode form anti-reverse connection protection.

2. Comparison between the original design and the current product: The original design has two levels of voltage stabilization, 7824 and 78 12, and the output constant current of each channel is LM3 17. The current product greatly simplifies the circuit, omits all unnecessary parts, and forms a very simple circuit, which is enough to meet the demand. The only pity is that the input-output voltage difference of 78 12 is too large and the loss is large.