Supercapacitors

Supercapacitors are electrical components that most notably act like rechargeable batteries in the sense that they can be charged and then that stored charge can be used to provide power to an electronic load.


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Some basic rechargeable battery and supercapacitor property comparisons:

This is a brief summary. These are highly variable power sources/components. You must carefully consult the datasheet/manufacturer’s information and learn how to safely use them.

  • Rechargeable batteries depend on chemical reactions for their charging and discharging. The more they are used, the less effective they are, even when used within recommended limits.
  • Supercapacitors are solely charged by moving charges (electrons) which move relatively freely through conductive material. As long as voltage and current is kept within the supercapacitor’s limits (consult it’s datasheet/manufacturer’s information), it should not change it’s basic properties much, if at all, based on amount of use.
  • Batteries store more total energy for a given size, weight and cost than supercapacitors.
  • Supercapacitors can be safely charged and discharged much faster than batteries. They are often used when short bursts of high current are needed.
  • Batteries have a fairly large voltage range (depending on their chemistry) where the voltage doesn’t change much as they take in (charge) or provide (discharge) current. Above and below that range though, there is a much more rapid change in voltage while charging or discharging.
  • Supercapacitor voltage is directly influenced by it’s capacitance and the change in charge (current in amps times time in seconds). A 1 Farad capacitor needs one amp of current for one second to change 1 volt. Leakage is a problem though, where capacitors self discharge.

Small scale supercapacitor backup power circuit for a single LED video below. Click here to watch directly on YouTube!

Supercapacitors with high internal resistance

Capacitor and supercapacitor components usually have the property that they have virtual no resistance to current. However, some do have internal resistance. As always, make sure to limit voltage, polarization and current to safe levels for the particular component you are using.

Higher than normal supercapacitor internal resistance testing beginner learning electronics tutorial

Supercapacitors with internal resistance:

  • Current is limited to no more than internal resistance will allow.
  • Internal resistance will be considered series resistance with any other circuit resistance.
  • Parallel supercaps with internal resistance will be able to provide more current. Double for 2 equal value, triple for 3 equal value, etc.


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