Practical integrated power supply - power supply circuit - circuit diagram - Huaqiang Electronic Network

This is a practical integrated power supply with continuously adjustable output voltage. The output voltage is continuously adjustable from 1.25V to 37V. The maximum output current is 1.5A. The circuit is simple and suitable for amateur production.
Circuit principle:

As shown in the figure, the output current of the LM317 is 1.5A, and the output voltage can be continuously adjusted from 1.25V to -37V. The output voltage is determined by two external resistors R1 and RP1. The voltage difference between the output terminal and the regulation terminal is shown. For 1.25V, this voltage will generate a few milliamps of current. After R1, RP1 to ground, a varying voltage is applied to the RP1 to the regulation section. The output voltage can be changed by changing the RP1 range. Note that in order to obtain a stable voltage output, the current flowing through R1 is less than 3.5mA. The maximum power consumption of the LM317 is 2W without a heat sink, and the maximum power consumption can be up to 15W when a sufficiently large heat sink is added. VD1 is a protection diode to prevent the output of the regulator from short-circuiting and damage the IC. VD2 is used to prevent the input short circuit and damage the integrated circuit.

Device selection and production

Rectifier bridge should use current greater than 3A and withstand voltage greater than 50V, diodes VD1, VD2 select 1N4002; C1, C3, C4 select electrolysis with voltage greater than 50V; C2 select ceramic capacitor; resistor with 1/8W carbon film resistor; RP1 select 5.1K potentiometer.

This circuit can be used without any debugging as long as the components are installed correctly.