Pls.help me how to make this project? I just need to use LM317 and this supply delivers 1.25 to 22Vdc and will deliver also a 600mA output current. What is your analysis about this or any conclusion regarding this matter?thanks...
You forgot to provide a link to the project. Maybe it has errors.
For 22VDC output the LM317 must have an input of at least 25VDC from the rectifier and filter capacitor. Then if you adjust the output to 1.25V the LM317 has almost 24V or more across it. Its datasheet shows that it reduces its max output current if it has more than 15V across it so its output at 1.25V might not be as high as 0.6A. It will be very hot and will shut down if the heatsink is not huge or if a fan is not used.
hello sir!can u pls. see my download attachment, it contains my circuit diagram of my power supply project.Can you also give your analysis about this.thanks a lot sir!
hello sir!can u pls. see my download attachment, it contains my circuit diagram of my power supply project.Can you also give your analysis about this.thanks a lot sir!
quote:Originally posted by audioguru
You forgot to provide a link to the project. Maybe it has errors.
For 22VDC output the LM317 must have an input of at least 25VDC from the rectifier and filter capacitor. Then if you adjust the output to 1.25V the LM317 has almost 24V or more across it. Its datasheet shows that it reduces its max output current if it has more than 15V across it so its output at 1.25V might not be as high as 0.6A. It will be very hot and will shut down if the heatsink is not huge or if a fan is not used.
The 24VAC transformer voltage is much too high. It will make almost 34VDC at the input of the LM317. The 220 ohm resistor is supposed to be 120 ohms for an LM317. Then the pot's value should be less.
Sir what will happen if i follow my circuit diagram? What are the possible risks for this?
quote:Originally posted by audioguru
The 24VAC transformer voltage is much too high. It will make almost 34VDC at the input of the LM317. The 220 ohm resistor is supposed to be 120 ohms for an LM317. Then the pot's value should be less.
You should read the datasheet for the LM317. But read it carefully because it also talks about the more expensive LM117 that can use different value resistors.
Adjustable power supply using LM317
Posted - Sep 22 2009 : 06:32:39 AM
me how to make this project? I just need to use LM317 and this supply delivers 1.25 to 22Vdc and will deliver also a 600mA output current. What is your analysis about this or any conclusion regarding this matter?thanks...
power.JPG
power.JPG