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Yes I'm very suspicious but the video reviews on the same ones from bang good were decent. Having said that I've read about Chinese "Quality fade" where the quality lowers to boost profits after a while, and fakes of course. We'll see
Bench power supply
- Thread starter Pappy2020
- Start date
I'm considering purchases of these:
0-30V, 0-3A:
https://www.sciplus.com/digital-display-dc-lab-power-supply-030-vdc-65480-p
Probably made in China, but has a label from a company with a long reputation to protect (Velleman).
5V, 8A:
https://www.sciplus.com/8a-5vdc-power-supply-65520-p
They give you a 15% discount for signing up.
0-30V, 0-3A:
https://www.sciplus.com/digital-display-dc-lab-power-supply-030-vdc-65480-p
Probably made in China, but has a label from a company with a long reputation to protect (Velleman).
5V, 8A:
https://www.sciplus.com/8a-5vdc-power-supply-65520-p
They give you a 15% discount for signing up.
Would prefer not to have a switch mode unit, also want to start out by building something thet will be handy to have around, will also be trying my hand at electroplating, (Mrs P makes arty things she sells and would like to see how they would turn out)
@Pappy2020
Most of the novice amateurs tend to fancy they have to build their own power supplies with incredible high voltage output and huge high current capabilities because they have no real idea of what voltages and what currents!! they could be needing for the unavoidable simple first projects.
It will take many disasters like trying to build that humongous PSU in the OP to get the feeling of the dissipated power thus requiring heat sinking and a fan.
Been there, you cannot imagine how many times in life. Time and money spent trying to build things I would never need.
My honest syggestions to the TS:
Throw away that ridiculos cartoon.
Download the datasheet for the LM317.
Learn to read a datasheet.
Read it and then you won't write "Why not 0 - 37?"
Build the simplest adjustable regulator you can with no more than 12V DC output. (Soldering in the air could take less than one hour).
Confirm how it works.
Start experimenting.
If the virus did not take me away, in one year we could meet here and check how many Amps more you really think you need or, better, you build one PSU with fixed voltages. My way for the last 12 or maybe 15 years.
Buena suerte.
PD: time is the sole asset nobody can recover.
Most of the novice amateurs tend to fancy they have to build their own power supplies with incredible high voltage output and huge high current capabilities because they have no real idea of what voltages and what currents!! they could be needing for the unavoidable simple first projects.
It will take many disasters like trying to build that humongous PSU in the OP to get the feeling of the dissipated power thus requiring heat sinking and a fan.
Been there, you cannot imagine how many times in life. Time and money spent trying to build things I would never need.
My honest syggestions to the TS:
Throw away that ridiculos cartoon.
Download the datasheet for the LM317.
Learn to read a datasheet.
Read it and then you won't write "Why not 0 - 37?"
Build the simplest adjustable regulator you can with no more than 12V DC output. (Soldering in the air could take less than one hour).
Confirm how it works.
Start experimenting.
If the virus did not take me away, in one year we could meet here and check how many Amps more you really think you need or, better, you build one PSU with fixed voltages. My way for the last 12 or maybe 15 years.
Buena suerte.
PD: time is the sole asset nobody can recover.
I have spent a while searching on line and found where this unit originally came from, and those green things at the top are TIP2955’s, same colour as the LM317.
This is supposedly by a guy on another forum calling himself max.
KeepItSimpleStupid
- Joined Mar 4, 2014
- 5,088
I bought a Harrison Labs (gobbled up by HP) power supply from a local place (30 miles away) way back in the 70's. It was 10A, selectable 0-32 V which meant "not variable". I promptly blew it up and fixed it. I think it was 3 transistors at $0.75 ea. I was testing it with automotive headlights. It had been repaired improperly.
But, it wasn't until a few years ago, I got a manual. It was designed as a linear supply with foldback current limiting that would be used as a fixed supply in some instrument. You had min/max somewhat hidden and a screwdriver adjustment on the front.
When you configured it for a new voltage range, you wold have to change transformer taps.
A short on this supply was cool. Voltage went to zero, current went to 10A. I basically needed that to operate a Tape deck solenoid in a factory car radio.
Then I picked up another PS that was part of equiptment. uA723 based, about 1A; ~12V, ~5, ~-12 adustable with a trimmer. It doesn't like being fed voltage.
But, it wasn't until a few years ago, I got a manual. It was designed as a linear supply with foldback current limiting that would be used as a fixed supply in some instrument. You had min/max somewhat hidden and a screwdriver adjustment on the front.
When you configured it for a new voltage range, you wold have to change transformer taps.
A short on this supply was cool. Voltage went to zero, current went to 10A. I basically needed that to operate a Tape deck solenoid in a factory car radio.
Then I picked up another PS that was part of equiptment. uA723 based, about 1A; ~12V, ~5, ~-12 adustable with a trimmer. It doesn't like being fed voltage.
KeithWalker
- Joined Jul 10, 2017
- 3,607
I have several power supplies in my workshop . One is up to 24 volts, 50 amps. It weighs a ton and I rarely use it. What I use most is an old Graymark Model 808 breadboard kit that my daughter built 35 years ago when she was taking a technology course. It has a fixed 5 volt 1 amp, a 0 to +15 volt 300 mA and a 0 to -15 volt 300 mA supplies with three breadboard strips built in. It uses simple linear regulators and has never failed me.
I would suggest that you build something similar. If you need to do electroplating you can build a dedicated supply for that later using the skills and knowledge you will have gained.
Regards,
Keith
I would suggest that you build something similar. If you need to do electroplating you can build a dedicated supply for that later using the skills and knowledge you will have gained.
Regards,
Keith
Why? Most of the commercial units are switching supplies.
Instead of trying to build one power supply that's going to be for every possible use you can conceive of, build several. You'll see the reasoning once you start building circuits. I have many circuits on solderless breadboards and prototype boards and one supply is never enough.
When I built my first power supply, it was a dual. One side was adjustable with a range of about 5-20V at less than an amp. The other side was adjustable around 5V at about an amp. I built it in the 70's when TTL was still popular. I still use it, but power most of my circuits from wall warts and USB chargers.
I love the 60V 40A supply from Danyk.cz (note the language bar to set the English) on basis of UC3842/43/44/45. Inspite of the Wikipedia "experts" erased my addendum to Wiki article Rectifiers about very rare but effective "strange" rectifier I may witness it works even better than "normal" one. However this is sure not Project for newcomer in electronics.
Could you explain briefly or start a thread on that Janis?
Hi Janis, Some interesting stuff on that Danyk link, though I think I'll get up to speed on things a little smaler
as for the power supply, looking for a linear version, bit easier to build, and I'v probably got a lot of the parts needed laying around here already.
Brett Peterson
- Joined Apr 26, 2019
- 3
Winding your own transformer, you can have several windings/taps to give you a high, mid, and low range for voltages if you want to stick with linear regulators.
A bit more advanced solution would be a switching regulator set up as a follower to a linear regulator, but you can always build that later as your familiarity with the engineering around regulators advances.
My own primary Bench Supply is just a generic replacement laptop supply that puts out 19.5v at up to 7.7 amps. Unless you need to boost it, you can use 78xx, 317s, 1117s, or anything else to drop the voltage down and have negligible ripple. The barrel jacks are easy to find and solder to prototype boards so you don't have to hard wire it to anything. You will probably want to get some heat sinks going with linear regulators, though.
I mostly use LM2576s (got a deal on 100ct) for my regulators, but they're switchers. They're good for up to 3 Amps, without pass transistors or big heat sinks, so worth a bit of ripple and some math. Once I get my oscilloscope up and running I can add better filtering to my regulator designs.
A bit more advanced solution would be a switching regulator set up as a follower to a linear regulator, but you can always build that later as your familiarity with the engineering around regulators advances.
My own primary Bench Supply is just a generic replacement laptop supply that puts out 19.5v at up to 7.7 amps. Unless you need to boost it, you can use 78xx, 317s, 1117s, or anything else to drop the voltage down and have negligible ripple. The barrel jacks are easy to find and solder to prototype boards so you don't have to hard wire it to anything. You will probably want to get some heat sinks going with linear regulators, though.
I mostly use LM2576s (got a deal on 100ct) for my regulators, but they're switchers. They're good for up to 3 Amps, without pass transistors or big heat sinks, so worth a bit of ripple and some math. Once I get my oscilloscope up and running I can add better filtering to my regulator designs.
Well it arrived today and it is well made, all modern SMD components inside. No product fade to report.
You can't go wrong for £45
