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    Impressive. It is not easy to charge the 150ah battery with solar panel directly. For proper charging using solar panel you just need to use a solar charge controller. You must also place the batteries in parallel connection for fast charge. Using solar charge controller avoid reverse current flow from Battery to a solar panel and unharmed pannels from burning. For proper charging your solar panel must create power more than 150w 150w is the threshold point for your charging. More the power added ……charging rate improve.
  4. Hello, We have some all-SMD, FR4 PCBs which comprise LEDs and Driver components, or some PCBs which have just driver components. These PCBs are either double sided or 4 layer. They are 1.6mm in thickness. The components range from D2PAK FETs down to 0402 resistors, and 4mm by 4mm SMD LEDs. We are sometimes finding that these PCBs, when delivered to us, don't work because of dry-jointed LEDs or other components. We find this out because we can often make PCBs work by simply 'dunking' on/near the component pads with a big , wetted soldering iron. However, we really need a better way to reflow these SMD components. Do you believe a hot-plate would be best?, or some kind of little SMD oven?, or an IR oven? Sometimes the dry-jointed components have connection to a thermal copper pour on the PCB bottom. -But sometimes this is not the case. We are actually wondering if the best & quickest way of doing it could be to simply put the PCB on a cheap hot-plate and waft over the suspect dry-joint components with a "gas gun" soldering tool?..(blowing scorching hot air on the suspect components)
  5. Came across this at work ....... There are a bunch of Siemens 3 phase thyristor modules being driven by a 200Hz PWM @ 24V. The thyristor modules seem pretty simple - put 24v on and it will turn on the three phases when they zero cross. Remove the 24v and they turn off. Now ........ surely trying to drive them with an unsynchronised 200Hz PWM is going to cause phasing issues ? The PWM is run through a PID loop to control heater temperatures but say for example we have a 10% duty perfectly synchronised with our 50Hz mains, the start of the PWM pulse will be at the zero crossing point of the 50Hz mains therefore will never turn off. If the PWM frequency was (for example) not exactly 200Hz, i.e. 200.0001Hz, we could be in a situation where you'd get a phasing effect and the output would turn on and off only when both the PWM and the mains frequency were within a certain part of the phase. Your thoughts ?
  6. Last week
  7. 0-30 Vdc Stabilized Power Supply

    Hi Tintin, You have done excellent work building this power supply and your experience is valuable for all other members. I encourage you to translate the PDF in English so anyone can benefit from it. Looking forward seeing your measurements and thoughts building this PSU.
  8. 0-30V Stabilized Power Supply

    Hi everyone. I've built one of the early 3A versions of this project several years ago. Its has worked very well after making the upgrades recommended by Liquibyte and audioguru (Thanks very much). I am planning to build a 5A version with a few additions of my own. I have added an arduino NANO which will measure and display AMPS and VOLTS, a cooling fan control which uses 2 CPU fans and heatsinks to cool output transistors, a bar graph display for current limit setting, buzzer for current limit warning and a relay to enable/disable power supply output. Using the output relay avoids needing the soft start delay to avoid the output transients and can disable outputs with press of a button. I've attached schematics of my current version for anyone interested. After seeing design by Imester using 2 transformers to step up or down the output voltage, I would like to integrate something similar into my design using 2 12V center tapped transformers instead of a single 24V. Could easily use arduino and relays to control which transformer secondary windings to use depending on Volt Adj pot setting. Does the opamps need their own separate supply voltage for this to work properly or could it simply use Vin as it does now? Any ideas and suggestions for a dual transformer setup or the overall design are welcome. power supply 30V 5A v5 page2.pdf power supply 30V 5A v5.pdf
  9. To replace 8 AA's with Li-ion's you will need to make it three, not two. I suppose it depends on how sensitive the equipment it, but I myself use 3X 14500 batteries in my radio control remotes instead of 8X NIMH or alkaline AA's. I use dummy batteries to fill in the spaces. Capacity will be down, but in my case I don't mind as the batteries in the remote will outlast any of the batteries in the actual vehicle you are controlling with the remote.
  10. Bar code reader

    Using bar code technology in stores can help to solve all these problems. It lets you keep a centralized record on a computer system that tracks products, prices, and stock levels. You can change prices as often as you like, without having to put new price tags on all your bottles and boxes. When purchasing a bar code scanner you want to ensure that it has the right wireless connections. This usually depends on how you to collect and input data into your inventory system.
  11. nodemcu and Ai a6 module

    Hi and welcome to our community, To help you out we will need more information about your connections and software used. A clear schematic will help us locate any issue and your code will provide additional insight.
  12. 0-30 Vdc Stabilized Power Supply

    Hi, I just finish my power supply ! I made a PDF document (with a lot of picture and explanation) who resume all the story about this adventure, and made a lot of measurment ! It is in French but I will translate in English soon. I thank all this community, who made a great job ! I join you some photos and my work on a PDF format. Alimentation0_30V.pdf
  13. nodemcu and Ai a6 module

    HI Everyone Im trying to connect the A6 Module to a nodemcu Version 3.without success, Does anyone have experience how to set this up and communicate between the 2 modules? All help appreciated Thanks Meir
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  15. 0-30 Vdc Stabilized Power Supply

    When you turn down P2 to zero then the project's output current should be no more than a few mA. The circuit reduces the output voltage with U3 and D9 to reduce the current. When the current is limited to a few mA then the anode of D9 is 0V and its cathode which is driven from the output of U3 must be about -0.65V. That is why U3 is an opamp that has its input and output able to go close to its negative supply and why it has a negative supply. When you turn up P2 then the current does not go up, the voltage and the load resistance set the current. The maximum current goes up. The circuit is designed for a maximum current of 3A so you should set the current calibration trimpot RV3 so that with P2 at maximum and with the output of the project shorted then the current is 3.0A. If RV3 is set to its maximum of 100k then the maximum output current will be 1.33A as I showed in post #?.
  16. Hi, To achieve what you would like you need a programmable timer to be able to set the ON-OFF time at high precision. I don't know if you can find such timer in the market, as most timers are rated about 16A and are weekly programmable. What possibly you could do is to use a timer to set the ON time and keep the OFF time manually. In this case a timer like: may help.
  17. Hello, I would think few of us would know anything about mig welders. I gather you want to hot switch the current from the mains to the welder. What current does your welder draw would be a start. You may need a high current relay to do the switching. Like?!2966!3!166591437759!!!g!81032003877!&ef_id=WqqIQwAAAacd4m57:20180315145043:s It's rated "AC contract rating - relay: 25 amperes at 240 volts ac." You need a relay rated higher than it draws off the mains because of the inductive load - I gather the mig welders have a transformer at the input like an arc welder?
  18. 0-30 Vdc Stabilized Power Supply

    Hi Audioguru, Sorry I do not understand your last phrase " The opamp used for U3 and the negative supply voltage must be allow the output of U3 to go low enough so that the input to the output amplifier is shorted to 0V when the output of the project is shorted. Then R7 is the load. " If my memories are good, if I make a short-circuit when the POT2 is set to zéro, the Voltage output do not go down to 0V, and when I turn clockwise the POT2 the current go up. But I remember with this method, I have 3 A maximum wioth POT2 set to the middle, or if I put a load for 3A the POT 3 need to be max for 3A max. This is this difference who make me perplexed ! PS : I buy a new toroïdal 28VAC 160VA !
  19. At $109.95 its among the most overpriced test provides we have seen. All this would be bearable if the complement had something to show for itself. Sadly, you get to know nothing about the product from. You get no clue about the components in it. There is little mention of the dose. Pro Muscle Plus So you have no clue if the complement performs or is secure. The last straw in the provides are the monthly membership. I am sure you are not going to like the idea of paying $109.95 for it every 30 times. It would be best to stay away from this offer. Look for more trusted and affordable alternatives. Recommended Alternative Our suggested alternative, Pro Muscle Plus.
  20. 0-30 Vdc Stabilized Power Supply

    165mV/500mA= 0.33 ohms that is wrong. 215mV/1A= 0.215 ohms that is also wrong. 1.304V/3A= 0.435 ohms which is close to your measurement of R7. Then trimpot RV3 is set for a max current of 3A or less. When the output current is higher than the setting of P2 then the output of U3 goes low which turns on the LED and reduces the voltage at the output amplifier. Then the shorted output should have a current of 3.0A maximum. The opamp used for U3 and the negative supply voltage must be allow the output of U3 to go low enough so that the input to the output amplifier is shorted to 0V when the output of the project is shorted. Then R7 is the load.
  21. PCB manufactureres

    You should not spend your resources on a firm which will not guarantee that in advance. Check their operational capabilities as well as the sort of projects which could handle your business. When quality pitches in, you also have to know their testing procedure, particularly for connectivity.
  22. About buying and selling PCB

    It's not so hard I think. Because if you search on google you'll get lots of qualified pcb manufacturer websites. I found this one right now
  23. 0-30 Vdc Stabilized Power Supply

    Ok finally I test limited current and the voltage above R7 with 500mA is 165mV and 313.8mV with 1A. I measure with milliohmeter and I have 430mR for R7. I don't understand why the voltage drop is not 0.43*0.5=215mV and 0.43*1=430mV ? So I make some test : a) For max 3A output with Pot2 max I have to put 1.304V on U3+ b)It's works fine, if a put a 3.01A load (with my electronic load) the Led bright and the current limiter est working. c) But I test to make a short-circuit I blow up my primary fuse (630mA T, maybe to low). Why do you think about the voltage drop about R7 and for my 1.3V for 3A max ?
  24. WOW lots of help here.
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  26. 0-30 Vdc Stabilized Power Supply

    I use copper wire, not rice wire. They put rice in everything they make, especially batteries.
  27. 0-30 Vdc Stabilized Power Supply

    I find the problem of the fallen voltage, it is due to a Fucking wire like this who have a 2.8 ohms resistor : So I can test now the current limiter function correctly !
  28. 0-30 Vdc Stabilized Power Supply

    If my theory is good, the wire between output and banana plug have a resistance of 2.82R. How to calcul it : R1=U*R2/U2 - R2 R1=5V*10R/3.90V-10R=2.82R. That explain : a) why the chinese voltemeter "see" 5V and not 3.90V after bananaplug why with 10R load for 5V =>3.90V at output for 8V = >6.90V output for 10V =>7.50V output c) why, when i test with my electronic load, with 100mA on my electronic load I have a current of 282mA ! This evening I try to measure the resistor of the wire, I will change it tomorrow.
  29. 0-30 Vdc Stabilized Power Supply

    5V on 10 ohms produces a current of 500mA (0.5A). Then the voltage across R7 is 0.235V. On your schematic, C is the ground for the current regulator. The output ground is its input signal and the 11.2V is its reference voltage.
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