Capacitors choise

hello, i was wondering if my setup is somehow good from the capacitors pov, i have a 9v 0.6 A source that i used for powering an arduino with a 5v regulator, an nrf with an 3.3 regulator. i know that to much capacitance is bad but also not to low

You're starting a new thread on an existing thread that you started on the same subject. It wastes peoples time.

I cannot see your schematic very well, my monitor shows it mostly as gray. What I saw looks interesting and close. I generally use two bulk capacitors each large enough for the circuit, that way if one fails the other will be fine and the product will keep on working. From what I could see you did do that. What I did not see were high frequency bypass capacitors. You can check the data sheets for the regulators and check each brand you plan on using, they are not all the same.


I used some 206 and 104 for decoupling on the verry first 9v input, on each regulator and as i remember on pro mini input and other modules like nrf that nedded 47uF, 104 cap on input. I was wondering if values are good or if the psu has a low curent rate 0.6A, i won t have enought power to always keep charged the capacitors in the circuit. As i have more on each stage, they kind of add together. I don t find if i need capacitors on asm1117, i saw some say 10Uf some 20uf

The first one was about hc05 and this is about overall capacitors

Do you really? :astonished:

Why might that be?

I cannot answer that question without knowledge of the regulators and who made them. My suggestion is look at the datasheet from the manufacturer of the parts you are using. They will show a schematic and the recommended decoupling. More will not hurt. Extra capacitance on the input helps just as long as the source can power them. Also even more important are the high frequency decoupling capacitors without them the odds are high it will oscillate at some high frequency heating up and playing havoc with your system. Keep leads as short as possible and as close to the regulator as you can get them.

Within reason you can put as much capacitance across the supply as you like. Yes, there will come a point where you have too much but too much is so much that you are unlikely to get to that point with a reasonable number of capacitors of modest values. Don't worry about it.

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I also have a question, if my arduino board is doing nothing and have nothing attached to it, why if i power it from a phone charger 5v 1-2A it gets got as the regulator doesn t get in use ,and from the pc usb port it s fine and cold ?
Same, i have a hc05 module that doesn t send anything i also didn t sent any tx signal to it, it only waits for pairing and the led blinks and it gets hot, the middle processor or what s it, i was thinking of using a heat sink but can capacitors as they charge up, take to much power and cause the regulators to get worm even if i don t use that power with any module ? Same on a 12v relay, i am expecting that would be from the coil even if i have no load on it

When you attach power to the Arduino it is operating code of some type, probably the boot loader. I have a feeling your phone charger is not outputting a regulated 5 volts DC. It is probably putting out about 6.5V with lots of ripple or AC. Use something in the 9 to 12V range and use Vin. Could you post a schematic of the whole system?

the phone charger was just an example, i also had a hc05 conected to the arduino 5v pin and it went really hot even if i didn't used it so i got an external asm1117 5v regulator and now it is cold yet. i powered the arduino with a buck converter from 12v to 9v and input at raw pin and gnd of pro mini so that it regulates twice also the other asm1117 are powered at 9v . i can make a schematic but now i have only a photo with the board


Looking at your board I do not have a clue as to what is happening. My feeling is you have way to much load on the 5V system. The USB bypasses the onboard regulator so it will remain cold. A schematic will help clear this up.