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.