Can we replace same value capacitors in Cell phones ?

Thread Starter

paldgm

Joined May 26, 2017
13
I am new in micro soldering, is it possible can we replace same value capacitors with different Voltage readings in cellphones
Examples
Can we replace 1 micro F 25V with 1 Micro F 2.2V ?
What other parameters should we check before we make any decision on capacitors swapping.
Thanks in advance
 

spinnaker

Joined Oct 29, 2009
7,835
I am new in micro soldering, is it possible can we replace same value capacitors with different Voltage readings in cellphones
Examples
Can we replace 1 micro F 25V with 1 Micro F 2.2V ?
What other parameters should we check before we make any decision on capacitors swapping.
Thanks in advance
If you are asking this kind of question you don't have the required skills to be replacing caps in cell phones.

25v and 2.2V are the voltage limits of the caps. The cap in your cell phone has a much higher rating than the 2.2V of your replacement.

If you were to replace a steel beam rated for 1000 kilograms with one rated for 10 kilo grams. What do you think would happen when you placed 500 kilo grams on the beam?
 

Thread Starter

paldgm

Joined May 26, 2017
13
Thanks for your help spinnaker, Appreciate your help , I will always remember you , you are the first one who replied on my very first post on AAC , you are right , I am just trying to understand all concept and only working on old cellphone motherboards. Sorry my background is not from electronics, thats why it seemed like a dumb question to you (Hopefully i will ask some sense full questions in future)

Anyways could you please let me know if 25V and 2.2V are capacitors limits. So if i would like to replace 1 micro F 2.2V , Can i replace it with 1 Micro F 25V ? because of course 25V limit is higher than 2.2V or do i need to consider something else ?
 

spinnaker

Joined Oct 29, 2009
7,835
Thanks for your help spinnaker, Appreciate your help , I will always remember you , you are the first one who replied on my very first post on AAC , you are right , I am just trying to understand all concept and only working on old cellphone motherboards. Sorry my background is not from electronics, thats why it seemed like a dumb question to you (Hopefully i will ask some sense full questions in future)

Anyways could you please let me know if 25V and 2.2V are capacitors limits. So if i would like to replace 1 micro F 2.2V , Can i replace it with 1 Micro F 25V ? because of course 25V limit is higher than 2.2V or do i need to consider something else ?

If you were to replace a steel beam rated for 1000 kilograms with one rated for 10 kilo grams. What do you think would happen when you placed 500 kilo grams on the beam?

Hint the 2.2v cap is the 10 kilo beam. The 25V cap is the 1000 kilo beam.

What would happen to the 10kilo capacity beam with a 500 kilo weight on the beam? Sure it might work but not for long. If it does not break immediately you can be certain it will sometime in the future.

So ,what do you think would happen to the 2.2V cap if you exceeded its rated value?
 

ErnieM

Joined Apr 24, 2011
8,053
Generally yes, you can replace a part rated for 2.2V with a 25v cap.

However, caps can act funny sometimes when running at a small fraction of their voltage rating. Still you would be safe (no spitzensparken) and for many cases the circuit will work just fine.
 

Thread Starter

paldgm

Joined May 26, 2017
13
Generally yes, you can replace a part rated for 2.2V with a 25v cap.

However, caps can act funny sometimes when running at a small fraction of their voltage rating. Still you would be safe (no spitzensparken) and for many cases the circuit will work just fine.
Thanks that's only thing i would like to know, sometimes its really hard to find exact same rating capacitors from a donor board. I will try and let you guys know about the results. These are just test boards so nothing to loose here.
 

Tonyr1084

Joined Sep 24, 2015
4,889
Answer to post #1: No, you can't replace a 25 volt cap with a 2.2 volt cap. The smaller cap will explode.

Answer to post #3: Yes, you CAN replace a 2.2 volt cap with a 25 volt cap. However, internal resistances will be different and they may be the same capacitance but they will each behave very differently.

As a capacitor reaches it's charge voltage (upper limit) its resistance increases exponentially (speaking of DC currents and voltages) At lower voltages its internal resistance is approaching zero ohms (so to say). A completely discharged capacitor has no resistance. When voltage is applied, current immediately is at max current (ohm's law) but as it approaches the upper limit current drops way down (higher internal resistance)

AND there's different types of capacitors. Some are designed to have a low ESR (Equivalent Series Resistance) which respond differently to those with higher ESR ratings. Different capacitors are more stable with temperature changes but more expensive whereas some cheaper caps have greater operating tolerance ranges.

Trust me, I know very little about capacitors. I may be ahead of you but not by much on this. There's a good reason why some engineer chose the caps he or she chose. Yeah, you can swap a low voltage cap with a high voltage cap. But it's quite likely you won't like the results.
 
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