| T O P I C R E V I E W |
| gredz |
Posted - Sep 22 2009 : 06:32:39 AM
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...
Download Attachment:  power.JPG
24.09 KB |
| 11 L A T E S T R E P L I E S (Newest First) |
| audioguru |
Posted - Oct 09 2009 : 1:40:48 PM
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. |
| gredz |
Posted - Oct 09 2009 : 03:20:21 AM
pls. discuss this project for me dude!thanks.
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| gredz |
Posted - Oct 09 2009 : 03:18:34 AM
oh im so sorry! ok i will call you dude! |
| audioguru |
Posted - Oct 08 2009 : 2:57:21 PM
A SIR is someone who was Knighted by the queen of England.
I have never met the queen so please stop calling me a SIR.
Call me Hey Dude instead. |
| gredz |
Posted - Oct 08 2009 : 12:30:15 AM
i try to make it sir! |
| audioguru |
Posted - Sep 25 2009 : 11:57:49 AM
The input voltage is too high so the LM317 will be too hot and might shut-down or it will reduce its output current.
The 220 ohm resistor value is too high so the output voltage might rise without a load.
The datasheet for the LM117/LM317 explains these problems. |
| gredz |
Posted - Sep 25 2009 : 04:58:09 AM
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.
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| audioguru |
Posted - Sep 24 2009 : 10:18:39 PM
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. |
| gredz |
Posted - Sep 24 2009 : 9:55:36 PM
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.
Download Attachment: power.JPG
24.09 KB |
| gredz |
Posted - Sep 24 2009 : 9:49:24 PM
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! |
| audioguru |
Posted - Sep 22 2009 : 08:04:22 AM
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. |
power.JPG
power.JPG