Hacker News new | past | comments | ask | show | jobs | submit login

Using the word “accumulator” wouldn’t be enough to differentiate batteries from capacitors, inductors, etc. which are also accumulators.



> inductors, etc. which are also accumulators.

In what sense do inductors accumulate?

Batteries and capacitors accumulate (i.e. integrate) current.

Inductors differentiate current: v = L di/dt means you get voltage out of current changes.


The main way that inductors function is by storing energy in a magnetic field, exactly analogous to the way capacitors store energy in an electric field.


The voltage an inductor creates will restore the current. It's storage.

And while a capacitor's voltage is the integral of current, a battery's voltage isn't.


I think this might be why accumulate is a good term. If one needed an accumulator that regulated voltage an inductor might work.

Warning I barely know what I'm talking about.


If you apply a constant current to a capacitor, the voltage across the capacitor will increase linearly as the capacitor stores energy in the electric field.

If you apply a constant voltage to an inductor, the current through the inductor will increase linearly as the inductor stores energy in the magnetic field.

Perhaps part of why the intuition can break down is that in real life, inductors tend to be much "leakier" energy storage devices than capacitors. If you store some energy in an inductor and then change the voltage across it to zero (practically: short its terminals together), in theory a perfect inductor will maintain a constant current forever and the energy stored does not change. In practice inductors (with an exception for things like superconducting magnets) are made from wire that has a resistance, and so the current in a real shorted inductor will eventually decay to zero. This means that in practical terms inductors are mostly only useful for short term energy storage. On the other hand, real-life insulating materials (like air, vacuum, or Teflon) can can be pretty close to perfect insulators allowing real capacitors to store energy more or less indefinitely... certainly on timescales of years.


Inductors accumulate a magnetic field.


In system design that distinction may not matter.


Seems like capacitors, inductors and batteries differ only quantitively in their response curves, not in qualitatively? As in they all do different things to the circuit on the voltage, amperage and time axis? We would need separate words for them, but accumulators seems like a decent umbrella.




Consider applying for YC's Spring batch! Applications are open till Feb 11.

Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: