LM317 adjustable power supply electronic project
This LM317 adjustable power supply electronic project will provide a wide output voltage range from 1.5V up to 30V by selecting two resistances.
You can draw up to 1.5A from the LM317 , but if you need a higher current you can use an LM338T rated to 5A.
By using a potentiometer, R2, as one of the resistors you can dial up the output voltage wanted. Either AC or DC input can be supplied to the Kit via a socket or terminal block.
The input DC voltage to the regulator must be at least 2.5V above the
required output voltage ( if you want to obtain an output voltage of 30 volts you must to use at input voltage at least of 32.5 volts).
To be safe for continuous operation the maximun input DC voltage to the regulator should not be over 33V.
When external capacitors are used with any IC regulator it is good practice to add protection diodes to prevent the capacitors discharging back into the regulator in the event of abnormal operating conditions, like a sudden short circuit on the input or the output, or a back emf from an inductive load (D1 and D2).