The most important thing for analog power supply is filtering, surge prevention and interference suppression. Some power supplies have EMI behind them, and multiplexing makes the voltage more pure.

The box represents the rectifier circuit, which becomes DC after rectification. There should be no AC in the future. If there is, a circuit must be established to eliminate it. The rheostat regulates the voltage fluctuation, and the voltage fluctuation works! The following 1 element CX2 is a filter circuit, and the upper and lower groups are also filters (that is, the characteristics of inductance are used to block the flow DC). Use }5. 1K resistor to let the remaining alternating current pass, and then the alternating current at C 13 is short-circuited and self-exhausted!

Capacitance and inductance are commonly used filter circuits. Capacitors can only pass AC, but not DC. Inductor prevents alternating current from passing! But it has something to do with DC. As long as you understand this truth, the analog power supply is basically no problem!