Can I apply a voltage higher than a capacitor's rated voltage

In summary, the conversation discusses the use of a 5.5V .22F capacitor and a 6V LED for a school project. It is noted that running an electrical component at its rated voltage can cause damage, with the MTBF decreasing quickly as the voltage increases. The speaker plans on using the capacitor once or twice and is willing to risk minor damage. It is suggested to use a 220 ohm resistor to protect the LED from high current. The function of the capacitor is questioned, with the possibility of it having reduced capacitance due to being a ceramic capacitor. The use of a 6V battery is also mentioned as an option. The conversation ends with a question about the current drain of the LED.
  • #1
stephenkohnle53
I have a 5.5v .22F capacitor and I plan on using a 6v led on it for a project. Since I am not going to need to use it much and I am willing to do minor damage to the capacitor could I do that. By the way its for a school project so I will likely use it once or twice then keep it but never use it again.
 
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  • #2
When an electrical component is run at exactly its rated voltage, it will have a certain MTBF (Mean Time Between Failures). The MTBF decreases quickly as the voltage increases. At some voltage, it arcs over / fails / explodes / melts immediately. You will probably have no problems putting 6 volts on a 5.5 volt capacitor if you only do it once or twice. Any damage, however, will not be minor. The capacitor will either still be good, or it will be destroyed.
 
  • #3
Alright that is what I thought would happen, I think I will see how bright the led is, at say 5v and if it is bright enough then I will use that, otherwise I will use 6v. I got the capacitor from salvaged electronics so I can always get a new one if it gets damaged.
 
  • #4
Typically connecting a LED to 5.5 V (or 6 V) is an almost sure way of killing it.

You need to protect the LED from too high current.
 
  • #5
I was planning on adding a 220 ohm resistor. I did not calculate the ohms needed, I read that, that is a good resistor for it. I made a thread about the project here https://www.physicsforums.com/threads/how-to-wire-an-emergency-flashlight.934421/#post-5902730

I put this as a separate thread so others can see this for other projects instead of getting the information from a thread devoted to a flashlight rather than whatever someone else might be searching for. If you want to discuss the resistance needed please go to the other thread as for other protections needed feel free to put that here or the other thread
 
  • #6
Yes, with 220 Ω it should be OK, you have just not mentioned the other info earlier.
 
  • #7
Yeah, I have been up far later than I should disassembling things, so I am a little forgetful. Any way after school I will gather some switches then post the supplies I have scavenged in the other thread.
 
  • #8
What is the function of this capacitor?

If it is a ceramic capacitor, the likely effect will be that it will have only a fraction of its nominal 0.22uf of capacitance.
 
  • #9
My bet is that OP means not 0.22μF but 0.22F supercapacitor.
 
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Likes sophiecentaur
  • #10
Borek said:
My bet is that OP means not 0.22μF but 0.22F supercapacitor.
Thanks,
Didn't notice that...
 
  • #11
Why not just run the LED on 5.5V? It will stay alight at a much lower voltage than that.
Remember that, if you plan to use a Capacitor as a power source, its voltage will start to drop as soon as you connect the LED. (Unlike a 6V battery)
What is the current drain of the LED?
 

1. Can I damage a capacitor by applying a voltage higher than its rated voltage?

Yes, applying a voltage higher than a capacitor's rated voltage can damage or even destroy the capacitor. This is because the capacitor is designed to withstand a specific amount of voltage, and exceeding that amount can cause the capacitor to fail.

2. How much higher can I safely go above a capacitor's rated voltage?

It is not recommended to go above a capacitor's rated voltage at all. Even a small increase in voltage can cause damage. It is best to stick to the specified rated voltage to ensure the capacitor's proper functioning and longevity.

3. Can I use a capacitor with a higher rated voltage in place of one with a lower rated voltage?

No, it is not safe to use a capacitor with a higher rated voltage in place of one with a lower rated voltage. This is because the higher voltage capacitor may have different capacitance and other electrical properties that can affect the circuit's performance or even cause damage.

4. What happens if I accidentally apply a voltage higher than a capacitor's rated voltage?

If the voltage is only slightly higher, the capacitor may still function but with reduced capacitance. However, if the voltage is significantly higher, it can cause the capacitor to fail immediately or over time. It is always best to use the specified rated voltage to avoid any potential damage.

5. Can I modify a capacitor to handle a higher rated voltage?

No, it is not recommended to modify a capacitor to handle a higher rated voltage. Capacitors are specifically designed to withstand certain voltages, and altering them can result in unpredictable and potentially dangerous outcomes. It is best to use a capacitor with the appropriate rated voltage for your circuit.

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