audioguru2
- Apr 6, 2004
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I think somebody made a pcb design of the latest schematic.
Ich Will:
Is it for this one: http://www.electronics-lab.com/forum/index.php?action=dlattach;topic=7317.0;attach=16065;image
And do you have better resolution?
Audioguru:
What about original PCB... are there many changes from original design?
Is it for this one: http://www.electronics-lab.com/forum/index.php?action=dlattach;topic=7317.0;attach=16065;image
And do you have better resolution?
Audioguru:
What about original PCB... are there many changes from original design?
audioguru2
- Apr 6, 2004
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The original design used many parts that were too small and got too hot.
The new design is almost the same but uses some bigger parts to keep them cooler.
Driver transistor Q2 is in a different case and pins layout. Its heatsink probably will not fit on the original pcb.
The new design is almost the same but uses some bigger parts to keep them cooler.
Driver transistor Q2 is in a different case and pins layout. Its heatsink probably will not fit on the original pcb.
No, it for http://www.electronics-lab.com/projects/power/003/index.html
On SMD details. If take interest, can throw down *.lay file
Hi, Josko, you may want to be cautious about using a pcb designed for 3-5 amps and try to pump 12A through it. Although most of the components will only experience ma's, a few tracing will need to supply the full 12 A. Make sure they are wide enough. Also your main cap will need to be huge and will not be able to fit on the pcb.
Kevin Weddle
- Feb 23, 2004
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Is it somewhere in between a 0 volt power supply and a 30V power supply? You need to be more specific on the voltage requirements of the circuit. Your talking about designing a very expensive power supply. I would use a variable voltage regulator for most applications. If you have a general power supply, you can add variable voltage regulators to get the voltage you need.
audioguru2
- Apr 6, 2004
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Kevin,
This power supply project is supposed to have a regulated output voltage of 0V to +30V and a regulated output current of 2mA to 3.0A.
It gets much too hot to use an IC regulator. Its ouput transistors dissipate a max of 113W.
A regulator IC in a TO-220 case can dissipate only 18W .
This power supply project is supposed to have a regulated output voltage of 0V to +30V and a regulated output current of 2mA to 3.0A.
It gets much too hot to use an IC regulator. Its ouput transistors dissipate a max of 113W.
A regulator IC in a TO-220 case can dissipate only 18W .
Kevin Weddle
- Feb 23, 2004
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My mistake audioguru, I misread the posting.
I posted my pcb a few threads back, these are the pictures of the case i promised.
The front, one digital voltmeter broke because i didn't have a galvanic isolated supply for it. I'm building my own now, pictures of it are below. There are 2 leds, one for the current limitter and one wich glows green when the fuse is ok and red when it's blown. The little switch next to the red switch is to turn the fan on, i'm searching for a broken pc supply to get it's fan regulator.
The side, you can see the fan.
At the back i used this socket to power the power supply.
I only have one 2N3055 because i only got one heatsink. The top pcb is the power supply, the pcb beneath it is a 5V supply for my displays. I need to modify it so it can also supply -5V. On the top pcb is also a little transformer mounted because i needed galvanic isolation for my meters. When closed the fan blows directly on the 3 heatsinks.
You can see the two big electrolytic capacitors beneath the power supply pcb.
My self made digital voltmeter. It's vacation and i don't have the equipment to make a pcb like in school so it doesn't look that good but it gets the job done.
Mounted in the case of the broken meter.
I made this supply for my latest school project. I haven't used it yet but it regulates between 0 and 29V with all trimmers unregulated. So i think i can push more out of it.
The front, one digital voltmeter broke because i didn't have a galvanic isolated supply for it. I'm building my own now, pictures of it are below. There are 2 leds, one for the current limitter and one wich glows green when the fuse is ok and red when it's blown. The little switch next to the red switch is to turn the fan on, i'm searching for a broken pc supply to get it's fan regulator.
The side, you can see the fan.
At the back i used this socket to power the power supply.
I only have one 2N3055 because i only got one heatsink. The top pcb is the power supply, the pcb beneath it is a 5V supply for my displays. I need to modify it so it can also supply -5V. On the top pcb is also a little transformer mounted because i needed galvanic isolation for my meters. When closed the fan blows directly on the 3 heatsinks.
You can see the two big electrolytic capacitors beneath the power supply pcb.
My self made digital voltmeter. It's vacation and i don't have the equipment to make a pcb like in school so it doesn't look that good but it gets the job done.
Mounted in the case of the broken meter.
I made this supply for my latest school project. I haven't used it yet but it regulates between 0 and 29V with all trimmers unregulated. So i think i can push more out of it.
dejan5rovic
- Aug 11, 2009
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I decide to build this project. Only bad thing is, that I saw this topic after buying all parts.
After gr8 disappointment, I'll try to build it as good as I can. I draw something between old and new schematic.
Please tell me what you think and how can I make it better without changing OPamp.
I need about 20V DC output, and around 2,5 Amps for my testings.
View attachment 40571
After gr8 disappointment, I'll try to build it as good as I can. I draw something between old and new schematic.
Please tell me what you think and how can I make it better without changing OPamp.
I need about 20V DC output, and around 2,5 Amps for my testings.
View attachment 40571
Ductapemaster
- Aug 12, 2009
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I'm in the process of deciding on a design for a lab power supply, and this one seems to fit the needs that I have. However, I have been reading some of the forum replies and I have a question. Why are you guys using OP amps that aren't rail to rail? If you used a rail to rail amp, it would eliminate the need for the charge pump negative voltage generator and make life a whole lot easier. Am I just missing something, or is there a reason for using non-rail to rail OP amps?
Thanks,
Dan
Thanks,
Dan
audioguru2
- Apr 6, 2004
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Like the original project, the values for R4 and R10 are wrong and R10 connects to the wrong voltage.dejan5rovic said:
Also like the original project, the main filter capacitors are much too small.
Each 2N3055 output transistor needs a series emitter resistor for matching.
The value of R14 will need to be changed to match your reduced supply voltage.
audioguru2
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The latest modifications use easy-to-find MC34071 or TLE2141 opamps that have inputs and outputs that work at 0V with a single polarity supply. Their max allowed supply is 44V. But a low voltage negative supply is needed because the output of U3 must go negative enough (about -0.7V) to allow D9 to force the output of the project to 0V when the output is shorted.
