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lab power supply

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glinjik:
Well here is my latest incarnation fo your enjoyment i know its a bit odd adding a 317 just to regulate voltage to a fan circuit but it will work i only using what i have here so this is my solution now to build the last part circuit board is getting crowded bu here goes...

glinjik:
update the lm317 works great but i think still too much current coming in i wonder if i can add a resister befor 317 to restrict the current i fan only needs 0.15A and bd140 is getting hot as well 317 both need heatsinks

glinjik:
well looks like i found my own answer to this question due to not having the parts availabe or volt regu;ator i think the answer is a secondary transformer i have plenty of 12v trabsformers so im looking at tomorow to redraw scematic to include a secondery transformer with output straight to the fan control circuit 12v transformer only puts out 1a at most should solve the problem

george.b:

--- Quote from: glinjik on December 20, 2019, 03:19:23 pm ---that indeed would be a great idea.....but im using recovered parts and there are no markings on the zener i obviously checked its voltage but thats all i can go on other than its physical size

--- End quote ---

Fair enough. Well, the glass body Zeners you usually find on stuff will be 1W, tops. 500mW are also common.

MarkF:

--- Quote from: glinjik on December 20, 2019, 04:33:15 pm ---Well here is my latest incarnation fo your enjoyment i know its a bit odd adding a 317 just to regulate voltage to a fan circuit but it will work i only using what i have here so this is my solution now to build the last part circuit board is getting crowded bu here goes...

--- End quote ---

You have diode D6 in the wrong place.  No current will flow to the 2N3055 transistors where it is.


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