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| Thread ID: 102474 | 2009-08-20 06:36:00 | bench power supply | toonttm (14853) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 802856 | 2009-08-20 06:36:00 | I want to build a (cheap) varaible DC power supply. I want it to run from 0V to 12V max with enough current for hobby electronics. I can source a DC PSU from an old computer but want the output to be variable. I am not worried about a display as I can hook a cheapie multimeter to the output. I have googled and found a few circuits based on the LM723 IC but would appreciate any info that you can supply. |
toonttm (14853) | ||
| 802857 | 2009-08-20 06:58:00 | If you live anywhere near to Upper Hutt I could let you have one. 0-15 volts, 500 mA max stabilised output with switchable current output limits from 50mA to 500 mA. |
Terry Porritt (14) | ||
| 802858 | 2009-08-20 07:38:00 | Many thanks for the offer, kind sir! But...I actually want to build several supplies and the best price I can get is around $230 each... (They have nice digital displays, variable volts and amps, overload protected etc...viable if I wanted 1 but no go for several) |
toonttm (14853) | ||
| 802859 | 2009-08-20 07:48:00 | Cheap Auto (or whatever they call themselves) sell such an animal :) Otherwise, Trinity in the USA make a beautiful item for about US$170 :) |
Zippity (58) | ||
| 802860 | 2009-08-20 07:56:00 | Perhaps you could explain a bit further on what sort of information you are looking for, then we may be able to help. The LM723 is limited to about 150mA. Another IC is the three terminal LM317T, that will give variable output 1.2v to 37v max. and has a nominal maximum working current of 1.5A. |
Terry Porritt (14) | ||
| 802861 | 2009-08-20 09:41:00 | Or the LM338 K will handle a bit more - happy enough at 4 amps if it is not dropping too many volts | R2x1 (4628) | ||
| 802862 | 2009-08-20 10:01:00 | Sorry, after a circuit I can build that will allow me to put something like a PSU from an old computer (so DC, maybe 12V - 15V) and then dial in the output voltage. Not worried about displays as I can use a multimeter to set/check the output voltage and certainly not looking for anymore than 1 amp. Using for hobby electronics so want to use for powering pic/picaxe and 'other' general circuits on a breadboard so really no great load. Think I am looking for a complete circuit I can build around the LM723 (or similar) IC. I just came up with LM723 from google, never heard of it before. |
toonttm (14853) | ||
| 802863 | 2009-08-20 10:03:00 | Oh, but would like stable voltage once I have checked/set it with the multimeter. Guess later on if it is a successful circuit I would add some analogue displays (or even LCD through picaxe adc to get a display). At the moment just looking for a few different circuits I can build and try out. Thanks for input... | toonttm (14853) | ||
| 802864 | 2009-08-20 10:33:00 | Right. I will be out all day tomorrow, but I'll have a look around tomorrow night or Saturday to see what I can find, scan any circuits I find and upload them for you. With the LM723, if you ever need higher current then an external power transistor can be added to increase current capacity. |
Terry Porritt (14) | ||
| 802865 | 2009-08-20 10:54:00 | Have alook at these - www.instructables.com www.elecfree.com |
decibel (11645) | ||
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