#1:3 0-30V 2mA - 3A Adjustable DC Regulated Power Supply DIY Kit - Part 3 Mods
ฝัง
- เผยแพร่เมื่อ 11 ก.ย. 2024
- Modding the 0-30V 2mA - 3A Adjustable DC Regulated Power Supply DIY Kit Short Circuit Current Limiting Protection from Banggood.
Part 3 - Modding
Affiliate links:
Power Supply SKU179821 www.banggood.co...
3pcs Voltage display Green www.banggood.co...
Proto PCB's www.banggood.co...
Music (Intro):
Deliberate Thought av Kevin MacLeod licensieras under licensen Creative Commons Attribution (creativecommon...)
Källa: incompetech.com...
Artist: incompetech.com/
Banggood, SKU179824, Power Supply, 0-30V, 2mA-3A, DIY-kit,DC regulated Power Supply,
If we add another similar output transistors (ex.Q5/Q6/Q7..)in parallel with Q4, so that the bases of both transistors should be joined together, the collectors of the transistors should be joined together, and from emitters of each transistor to the output positive teminal should be add one resistor 0.22 ohm / 3-5W, in order to balance the power load of the four parallel connected output transistors Q4 and Q5/Q6/Q7.Does it possible to work for output current 10 Amps ???
Or must be some mod on current limit circuit ??
*of course the TR-secondary .gives 22-24Vac 10-12 Amps,
& the filter caps are be 10.000 μF+
thanks
I'm not the expert to answer this but here are something on the top of my head: R7 the current resistor need to be changed (resistance value and power rating), the rectifier diods D1-4 need to be checked if they handle 10A, and I'm thinking if transistor Q2 and components around need to be adjusted driving more base current for 4 power transistors.
And if the PCB can handle 10A
You don't need the 7805 regulator! The resistor value would need to increase if you use 24v, but the power will be the same. LED must be current limited not voltage limited (within reason).
+Michael Strauss If I use a larger value resister there will be a more power lost in the resistor P=IxIxR.
My LED forward voltage is 4V. With the 7805 there is 1V and 6mA over the resistor = 6mW with 24V supply there is 20V and 6mA over the resistor = 120mW.
Please correct me if I'm wrong, some times i fool myself 😀
Hi, why are you only getting 24V DV output?
The AC supply (transformer) I used didn't deliver 24V AC and because of that it's a bot low. But it can save the Op-Amps in the circuit. Feeding the circuit 24VAC can create an internal DC voltage inn the circuit that will fry the Op-Amps.
can I build more of these and put them in series or parallel? to get like 60v or 6a?
best regards
In theory yes but I would have a look at a circuit that can output the desired voltage/current directly.
Having 2 current limitation circuits in parallel or series can spell trouble.
If i understand corectlly, this circuit Power supply don't have short circuit protection, if accidentally touch plus ➕ and ➖, at the output!? How i ca-n do to add some components to achieve short protection!?
If You short the output the current limitation will kick in. The circuit will only deliver the set max current by lowering the output voltage.
Hello friend,
I was wondering if you could explaine how I should connect my little volt/amp display to pcb. I did connect the volt display and I see the variable voltage. But I am not sure how to connect the amp display to see the current state. Any help would be appreciated. Thanks JW
+jwhiting352 Amp (current) displays you have to connect in series with the load. Check that the amp display can handle the current, overloading a amp display will release the "magic smoke".
I have my self bought one amp-display-kit and will add it to my setup when it arrives in the mail :)
I look forward to your amp-voltage hookup :)
I have shoot the video but is not satisfied with the result because of a small mistake from my side.
But i hope the video and my misteke will amuse you all then i upload it :)
Look forward to it
+rahmansaid I have uploaded 2 new videos about current measuering, hope the info is useful.
thanks! Maybe you could add a video of that as another compent added. JW
+jwhiting352 I'll do that :)
Hey, I have this same power supply however I have some issues with it, the constant current light is always on, you showed that yours is working, what could cause it to not operate properly?
I've seen other videos too and it's sort of hit or miss whether or not the CC light works well or not.
You can find an old blog about the circuit with a description of the function of the circuit for trouble shooting. Has the psu been working from the beginning? Do you have any output voltage? Are you feeding the circuit with AC voltage?
@@KristianLaholm yeah, I'm giving it 24VAC on the input, the output voltage is a bit low at 27V max but it does 3A well and doesn't behave strangely aside from the CC light not working as it should
@@zUltra3D The only thing I can see is the PNP-transistor "9015" driving the LED or the 2 resistors biasing it 2K2 and 10K next to the transistor. If you want to play around and do some troubleshooting :)
@@KristianLaholmI have no idea, I measured the transistor and compared it to the datasheet, it all seems fine, the resistors look good, reflowed solder joints that looked bad and it stayed the same so I have no idea what else I should try, guess I'll have to live with it like this, oh well. Thanks!
This is the best video on that kit that I've seen, good work.
I only need a 12V PS so I'm using a 16.7V AC transformer. I only have a 12V fan so if I keep the 7824 would it put out a lower voltage because of the smaller 16.7V PS, and is it ok to run it like that.
I'm using a failed ATX PS as the case and throwing away the failed switching PS circuit board, so that all it has is box, a 12V fan, and input filter - 0.47uF cap and inductor -, that is connected directly to the 240V input socket inside the case. Is it ok to keep this filter or should I throw it out as well.
Thanks
+SidneyCritic ComedyHound Thanks :)
With that transformer (16,7V AC) my guess is that the 7824 will be putting out 20V DC, check the voltage with a multimeter before you connect the fan.
I would search for a 7812 too keep the fan safe :)
The input filter would I keep in place.
And be careful with 240V :) Good luck :)
Any idea what you think might be wrong if my current limiting feature stops working? I know the is good, i've been going through the board trying to make sure each component is good / not bust.
In this link you find a good description of the circuit that the kit is based on www.electronics-lab.com/project/0-30-vdc-stabilized-power-supply-with-current-control-0-002-3-a/