Adjustable DC regulated power supply works
(3) filter circuit: the rectifier circuit output voltage in the majority of the AC component to be filtered, resulting in a relatively smooth DC voltage of the filter capacitor C to meet RL-C = (3 ~ 5) T / 2, or T For the input AC signal period, RL is the equivalent load resistance of the rectifier filter circuit. (4) voltage regulator circuit: the function of the regulator circuit is to stabilize the output DC voltage, does not change with the AC grid voltage and load changes. Commonly used integrated voltage regulator has a fixed three-terminal regulator and adjustable three-terminal regulator. Commonly adjustable adjustable positive pressure regulator with CW317 (LM317) series, their output voltage from 1.25V-37V adjustable, the simplest circuit external components only a fixed resistor and a potentiometer. The chip has a transition, overheating and safe working area protection, the maximum output current of 1.5A. The output voltage Uo expression: Uo = 1.25 (1 + R2 / R1) where R1 generally take 120-240 ohms, the output and the adjustment of the end of the output voltage regulator, the output voltage Uo of the expression: Uo = 1.25 (1 + R2 / R1) The differential pressure is the reference voltage of the regulator (typically 1.25V). I uploaded the principle of switching power supply and write the above design.
The working principle, application and prospect of the voltage source. First, the working principle of DC power supply DC power supply is a 220V frequency AC power conversion voltage regulator output voltage of the device, it needs to go through the transformer, rectifier, filter, regulator four links to complete. The working principle of the four links is as follows: (1) Power transformer: is a step-down transformer, it will convert 220V AC voltage to meet the required AC voltage, and sent to the rectifier circuit, the transformer by the secondary side of the transformer voltage The (2) rectifier filter circuit: rectifier circuit converts the AC voltage Ui into pulsating DC voltage. And then filter the filter circuit to filter out the larger ripple components, the output ripple smaller DC voltage U1. Commonly used rectifier filter circuit with full-wave rectifier filter, bridge rectifier filter.
