-1
\$\begingroup\$

I am very new to electronics and trying to do something which I am not much aware of yet. I have a NodeMCU (based on esp8266) for which I need power supply of 5V and it required I guess more then 300mA for the properly working. I use to power it either by USB or mobile charger, which makes it working awesome so far.

But now I want to mount it to my own circuit so I can customise few things. So in order to create that power I have used a circuit diagram I found on YouTube.

enter image description here

The things is with this circuit diagram I can get the 5V power but the AMP is not what is needed, so my NodeMCU starts to heat up very quickly if I use this power supply and basically my NodeMCU looks damaged now.

So I just want to know few things :

  • How can I increase the mA in this circuit?
  • Is it reliable for 24x7 running for days or even months?
  • Is there any formula to calculate the capacitor (red capacitor from circuit diagram) I need to use to make it work?

I try to attach instead of 470uF 25v I replaced with 2.2uF 63v (it was available with me so thought to use this for testing purpose) it increased the voltage value. But the mA or power stayed the same.

For basic reference, I have 230V AC power supply.

Any guidance will be helpful here!

Thank you! (in advance)

\$\endgroup\$
  • 2
    \$\begingroup\$ If your NodeMCU heats up it is not because you don't have enough current...there is some other problem. Please show a schematic of the actual circuit you built, along with a part number for the zener diode. Be sure to show actual resistor and capacitor values on your schematic. \$\endgroup\$ – Elliot Alderson Feb 10 at 18:10
  • 1
    \$\begingroup\$ What in the absolute [censored] do you need 300 amps for‽ \$\endgroup\$ – Hearth Feb 10 at 18:25
  • 2
    \$\begingroup\$ Please just get a proper power supply. Capacitive dropper supplies such as these do not isolate your circuit from mains, leading to electrocution risks. Also, they are only practical for providing small currents. \$\endgroup\$ – marcelm Feb 10 at 18:27
  • \$\begingroup\$ @Hearth I want to have Mili Amps not Amps, sorry its my mistake. \$\endgroup\$ – user3201500 Feb 10 at 18:33
  • 1
    \$\begingroup\$ @user3201500 When you're new to electronics, please don't try to design anything that's going to go into your main switch board (by which I assume you mean your distribution unit or fuse box) \$\endgroup\$ – Hearth Feb 10 at 19:18
3
\$\begingroup\$

I am very new to electronics and trying to do something which I am not much aware of yet.

It is a very bad idea to begin electronics working on mains circuits. You should purchase a 5 V power supply with adequate current rating for your project. Ensure that it has the relevant safety certification marks on it.

I have a NodeMCU (based on esp8266) for which I need power supply of 5V and it required I guess more then 300amp for the properly working.

Your 300 amps requirement is most unlikely. Presumably you mean 300 mA.

I use to power it either by USB or mobile charger, which makes it working awesome so far.

Stick with the awesome solution.

But now I want to mount it to my own circuit so I can customise few things.

You need 5 V. There isn't anything to customise in this regard.

So in order to create that power I have used a circuit diagram I found on YouTube.

Oh-oh!

The things is with this circuit diagram I can get the 5 V power but the AMP is not what is needed, so my NodeMCU starts to heat up very quickly if I use this power supply and basically my NodeMCU looks damaged now.

It sounds like you gave it more than 5 V.

How can I increase the AMP in this circuit?

By careful design for operation with specified minimum and maximum load.

Is it reliable for 24x7 running for days or even months?

A well designed one might be.

For basic reference, I have 230V AC power supply.

This is the scary part. That power supply circuit does not isolate your Node device from the mains. All parts of it must be considered live and if you connect a programmer or laptop to it that will be live too. This presents a serious shock hazard to anyone coming in contact with the circuit.

Proceeding with this PSU is not recommended for safety reasons.

\$\endgroup\$
  • \$\begingroup\$ And to the asker: if you absolutely must avoid using a commercial power supply, make your own battery-powered one. With nice, easy to use alkaline batteries, not lithium ones. \$\endgroup\$ – Hearth Feb 10 at 18:37
  • \$\begingroup\$ I understand its a risk and I am taking all the precaution for it. I am not taking risk of my life, for a circuit :) So don't worry. I have a professional electrician with me. \$\endgroup\$ – user3201500 Feb 10 at 18:44
  • 3
    \$\begingroup\$ If you have a responsible professional electrician with you, they should have you duct-taped to a chair by now! \$\endgroup\$ – TimWescott Feb 10 at 19:12
  • \$\begingroup\$ You forgot to mention that if this was connected to a PC via a USB or serial port for any reason that USB is probably also fried. \$\endgroup\$ – Edgar Brown Feb 11 at 5:04
  • \$\begingroup\$ I once saw a student connect a protoboard via a bunch of alligator clips into long naked wires that protruded at least 10cm above the board. There were at least 8 wires carrying 110 in this fashion. I did what any responsible professional electrical engineer would do, take 3 steps back and give a tongue lashing to his instructor. \$\endgroup\$ – Edgar Brown Feb 11 at 5:11
2
\$\begingroup\$

For basic reference, I have 230V AC power supply.

Any guidance will be helpful here!

OK. Basic guidance - DON'T DO IT! STOP!

I know, you don't think that this is helpful. Trust me, if you keep this up, somebody may get hurt, and that somebody is very likely going to be you.

Until you have a great deal more experience, DO NOT do anything which involves sticking wires into wall sockets. Even if you use a wall plug and wires, the rest of your circuit is potentially deadly due to it being connected directly to the AC lines. So just don't do it.

How can I increase the AMP in this circuit?

That's not the problem. Since you've apparently damaged your NodeMCU, lack of current is not the issue.

Is it reliable for 24x7 running for days or even months?

If you do it right.

Is there any formula to calculate the capacitor (red capacitor from circuit diagram) I need to use to make it work?

The starting place would be formula for the impedance of a capacitor at a given frequency, but that is not the problem.

Instead, go on eBay and buy a cheap 5 volt supply.

\$\endgroup\$
0
\$\begingroup\$

The way that professional product designers approach this problem is that they look at the vast multitude of good, cheap 5V regulated wall-warts that are on the market, and they buy one. Or you buy 100,000 a year. Whatever. Unless you're selling millions of units, you just don't make these.

\$\endgroup\$
  • \$\begingroup\$ Or if you're trying to save every fraction of a penny that you can, which is where the asker's example gets used. I've seen it in cheap crap from ebay and aliexpress, but never in anything reputable. \$\endgroup\$ – Hearth Feb 10 at 19:20

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.