With nothing connected, I dial to "5.10" on my multimeter. Each little thing seems to impact the voltage output of this device, a 20ma led for example - like 4 of them can drop voltage BELOW 5 volts. It's still seems to be enough to power a Nano board.
Once I start adding accessories like a wireless module, a Nextion touch screen display - the voltage drops, so much it goes below the NEEDED 5.0v the Nextion requires in order to operate correctly.
Should I be dialing volts on the LM2596 module after everything is running? Because when nothing is connected it would read over 6.5 volts, and at this point is a mystery to me. I think the LM2596 is rated for at least 2 amps, and I'm using just under 900 ma. I was expecting the voltage to possibly drop if I got close to the output maximum of the power module.
I am not married to this device, I am willing to use something else - I am sure there is something better. I chose this because I was under the impression it was more efficient with energy, -vs- lm7805, since the project runs on battery power. I also want to use with 24v battery power, but just learned that the 35v capacitor will not tollerate 24v power for very long.
larryd:
Many/most SMPS require a minimum load to achieve proper regulation.
You may have to add a resistive load.
Make sure the input voltage is within specifications.
.
Ok - this is new to me. Should I be adding a resistor in series with positive output? I just use ohm - law, calcualte 5v * 1 amp, so 5 ohm / 5 watt resistor.
I am not suggesting you will need to draw a large amount of current, just a need some minimum amount.
Try some different scenarios to see if you can effect better regulation, if not, then a better quality/designed board may be necessary.
I also use PS similar if not identical to those and have had no problems, however, the circuits I have used them with are not too sensitive to supply voltages.
I seldom run them at top rated current.
Tom: I am measuring the voltage, on the output pads of the LM2596 module, when I add components to the output 5v supply lines. The input voltage of 12v (and 2.2 amps according to the cheap voltage / current LED monitor) does not appear to change.
larryd: Yes this isn't my first time using the module, I usually just set them at 5v and go on as usual. I have problems with this project, after ping-pong game with Nextion tech-support, they explain the power supply must be 5v in order for device to work correctly. It will work at around 4.9 volts, before I start having problems.
After I discovered this, I went back and started checking voltages and realized how ridiculously sensitive the voltage was to every little 20 ma component added.
I only have a 1n4001 diode on the +5v out line to stop the power from going back up into it where I had a LED power switch. Of course, I am measuring the voltage before and after this diode which is the usual .7v drop, so I dial the LM2596 up to compensate for that.
DocStein99:
Ok - this is new to me. Should I be adding a resistor in series with positive output? I just use ohm - law, calcualte 5v * 1 amp, so 5 ohm / 5 watt resistor.
Just put a 220 resistor across the output or something.
The LM2596 is a pretty old thingy. If you want to stay in the Aliexpress cheap range (which I think is fine), I would look for the MP1584. Else, Pololu stuff is indeed great.
Hi,
I would now be doing a A and B check with DMM to see if resistors on the PCBs are the same.
Check that the inductor is properly soldered in.
Find the Vin and Vout of the IC and do a A and B check.
Check the voltage at the feedback pin.
larryd: The "green" boards I see, have TWO potentiometers. Does yours have 2 or 1? Mine has 1.
If this one is broke, is fine I throw away a whole $2.00 or something. But I do not want to buy any more unknowingly, since this is a bigger headache than it's worth.
I think I have some MP1584 in my box of stuff I haven't tested yet - I'll compare that one too.
The poloulu site is interesting, but at $10+ each one - buy 10 at a time is $100 just for little step regulators. Maybe I've been spoiled too much with eBay prices.
I look at it as my education - learning how to test and know the difference. I can't trust anything just because it cost more, and likely to be sold something that's broke that would actually be expensive.
Alot of times when I am unsure, I'll buy 1 of the cheapest- then look for the same thing that cost more but looks a little different from a different vendor or 2 different other ones. If I have just one of something I can't really compare it against anything else.
I'm going through some real trouble buying SOLDER now. I had ROLLS of solder from my father's garage I used forever, and ran out. I can't tell what it is, what brand - but the stuff is what I was used to using melted low and pooled up is just what I had been used to using for like 5 years. Radio shack out of business, I used to buy solder from there. gone through like 4 different solders so far order from Ebay, and they keep crumpling up making a frozen weld, flaking off - I can't figure out what's going on but my iron is way too hot over 320(C) at times and this is killing me.
I had problems getting 60/40 @.3mm solder ordered in, took 6 months.
However, 63/37 gives a much brighter preferred joint when cooled.
Get a good tempertature controlled iron, I have settled on Hakko (FX88D) after many years of using Weller. I use it at 350'C mostly.
Also, use liquid flux.
Wash boards with IPA (use old tooth brush) rinse with water, blow dry.
.
I use the TS 101 soldering iron, is my favorite one - its slender and handles up to 400(c) - I can use it to solder 8 gauge wires, or 28 gauge wires (and proto boards).
I never needed to use flux, or clean something spotless. Whatevwe was in the Radio Shack solder, I could touch iron back to a big ugly pile of snot, and it would liquify nice, and stay that way until i removed iron.
Over last months, I keep ordering different solders, and keep getting this FROZEN DRY solid, half way through. It flakes off, and there isnt enough space here for me to list all my complains. I just ordered some KESTER 60 40 lead solder, so I will see what happens. I have to order small samples because I do not want to get stuxk with a large spool of CRAP.
My only other option, is the Micro Center warhouse, is 40 miles away. Its a Radio Shack on Steroids. I know I can ask manager to sample the solder at the store, before I buy it. They work with their venders and treat customers like gold.
