Thanks liquibyte I was guessing I could use a 1n4007, but looks like the BR805D Max. Average Rectified Current is 2A and the 1n400X is 1A? Is that ok?
http://makezine.com/projects/0-24-Volt-2-Amp-Bench-Top-Power-Supply/
As far as this build goes, isn't that fuse for the variable side a little underrated at 1A for a 5A transformer?
No one here has ever really put forth a great hobby design to be honest even though bad ones flow through all the time. Perhaps we need to put together a low part count, solid performing first build for the new folks here and point them to that build when these things get proposed.
No one here has ever really put forth a great hobby design to be honest even though bad ones flow through all the time. Perhaps we need to put together a low part count, solid performing first build for the new folks here and point them to that build when these things get proposed.
Great idea! I would immediately be willing to contribute. But what would be the specs?
Something like 0-15V @ 1.5A linear regulated. Maybe some additional fixed voltages, too like +/- 15V and 5V for analog stuff and logic ...
hmmm im building an upgrade : 0-24v, 0-5A variable current limit ... the PCB is on the way from SEEEDstudio
the 5A is lm317 piggy backed with power PNP. one of those generic 5A types
current limiting is using PMOS, but ... im not sure if the PMOS will work, its a conversion from a simulation
this is the pic of the heatsink to be tested on (10cmx15cmx3cm) ... ribbed fins. this is actually the most important component i think
the supply comes from a generic 24V 200w PWM power blocks adjusted upwards to about 28v
the worse part of any power supply is sinking heat ... its like vomit ! arrgh
oh def a fan ... @ full draw = more than 125w of very angry electrons
and it will be inside a plastic "bin" of sorts lol
(upgrade from this "bin" of volts not bad for 1.5years of use , lm317 7805 n a 7812 http://3roomlab.blogspot.sg/2013/04/036-most-unlikely-psu-mod-lol.html)
Thanks for all the answers, that schematics proposed is way more complicated than what I'm looking for.
It's great to see my simple question sparked this design idea, I might wait and see what comes out of it and build that.
But, if you happen to come across some neat design, please let me know.
what kind of failure on transient? can you illustrate via a ... ermmm graph?
An LM317 or LM350/K design would be a lot simpler then that for him. fuse, transfo, bridge rectifier, a few capacitors, LM 350 or K on a large heatsink, resistor, trim pot to control the voltage and you got yourself a power supply. I built one when I was a kid and even etched my own very simple pcb board at the time. Was my first electronics project and it's still one of my regularly used power supplies today. The LM350K has built in short circuit protection/current limiting and reliable as hell, never failed on me.
Have you tried to delay the power up of the op-amps for 40-50mSec?
Here, try this one. It's got a few issues that we're still working on but it works rather well for the most part and should be a good first power supply. If you really don't want to take the time to have the boards made or don't quite have the confidence to try this out on a perfboard or something similar, I can send you a board I had made. I keep trying to get someone with the right test equipment to build and test this and help us figure out where the failure on the transient is coming from but I've had no takers so far so I'm willing to give the last two boards I have left away to anyone that wants them.
http://makezine.com/projects/0-24-Volt-2-Amp-Bench-Top-Power-Supply/
That sir, is a VERY CRAPPY build instruction!
...
(2) Ridiculous case! Wood is definitively not recommended to build enclosures that house components operating on the mains...
There are however tons of good DIY projects out there.
For example: http://hpm-elektronik.de/nt30-4-netzteil.htm
Here, try this one. It's got a few issues that we're still working on but it works rather well for the most part and should be a good first power supply. If you really don't want to take the time to have the boards made or don't quite have the confidence to try this out on a perfboard or something similar, I can send you a board I had made. I keep trying to get someone with the right test equipment to build and test this and help us figure out where the failure on the transient is coming from but I've had no takers so far so I'm willing to give the last two boards I have left away to anyone that wants them.
Nice supply!
But I can't wrap my mind around the supply of the current-limiting opamp. Why is the zener in series with the opamp supply? There will be a constant 10V drop over the zener but the supply of the opamp would not be regulated at all?
But apart from that, I also believe that the inrush-current of the main filter-cap is the cause of the glitch. The cap might have a quite low ESR and therefore the input voltage will drop a lot until the cap is charged. Hence the series pass transistors are saturated more under this condition. But a few ms later the cap is fully charged and the regulation circuit is not fast enough to compensate ...
My suggeststion: Insert some delay to turn on the output. Maybe as simple as an RC timing element and one FETto clamp the set voltage to zero or something the like ...
While I agree that it's a pretty crappy project for most of the reasons given I would argue against your point about the wooden case. A well made wooden case is less of a fire hazard than most plastic boxes, is mechanically stronger for something like a power supply with heavy transformers and is insulating enough to give good secondary protection against electric shock. That particular case isn't great but good cases can be made from wood. The most important thing to be careful of with insulating cases is to avoid conductive screws, transformer mounting bolts, etc passing through the enclosure unless they are prevented from becoming live by some other aspect of the design (being insulated on the inside or being earthed).