Questions tagged [batteries]

Devices to store chemical energy and convert it to electrical energy.

424 questions
Filter by
Sorted by
Tagged with
118 views

$E=mc^2$ tells us that everything has energy. So why can't we use anything as a battery/power source?

My body has mass, the floor has mass, the air has mass. According to the formula E=MC2, we can get insane amounts of energy with very very very small mass (looking at you antimatter). However our ...
68 views

Bike light: what consumes more current, continuously on or blinking?

I've been riding my bike many nights wondering the following question: What consumes my LED bike-light battery: the continuously on setup or the blinking setup? It might seem trivial, since the ...
16k views

Path of an electron through an electric circuit

When a potential difference is applied across a conductor, and if an electron moves from the negative terminal of the battery and reaches the positive terminal, then I want to know if the electron ...
771 views

If a battery is open on one end but connected on the other, does it raise the potential on the connected end?

If a battery has one end open and other end connected to a circuit will the battery increase the potential at the point of connection?
9k views

Relation between Terminal Voltage and EMF of a cell while the cell is being charged

I know the relation between the terminal voltage, V and emf of the cell, V' while charging given by V = V' + Ir where I = Current in the circuit and r = Internal Resistance of Cell Can anyone ...
2k views

Can a capacitor be charged without having resistance in the circuit?

I was looking for the fact when a capacitor is directly connected to battery without resistor what will happen? If possible then tell the time for charging.
95 views

What resistor should be connected to a $12\,\rm{V}$ battery for a $9\,\rm{V}$ output?

I have a $12\,\rm{V}$ car battery and a $9\,\rm{V}$ toy piano. I want to power the piano through the battery but the voltage is too high. What resistance should be connected to this circuit so that ...
49 views

I need a 12V battery supply for a device can I just connect four 3V batteries? [closed]

its for a modem which requires a 12v adapter, 1amp. So I tried connecting 4 batteries and also 5 but it never turned on and I couldn't figure why?
66 views

What's a reasonable difference in resistance between batteries in parallel?

I know that the differences in resistance between batteries in a circuit will create different drop, and as a result draw unequally. Unfortunately, I couldn't get my hands on a parallel D-cell ...
2k views

Current flow with batteries in series vs parallel

Taking let's say three ideal and identical batteries, why does the current flow increase when we add them in series compared to them being in parallel? I can understand the height analogy for voltage ...
4k views

Energy loss due to internal resistance of a battery?

Say I'm using a battery to power some process, and the internal resistance of the battery is given. The resistance of the process is not given, but assume it is minimal so the circuit runs at maximal ...
134 views

Can a capacitor be charged with multiple batteries connected in series [closed]

I connect 2 9-volt batteries in series. Then I connect that to a capacitor. Will that then charge the capacitor to 18 volts?
733 views

How does the voltage source provide energy in a circuit?

I understand that a voltage source drives the current to flow from the terminal with lower potential to the terminal with higher potential. However, if the electrons are gaining potential energy then ...
80 views

Can an electric car be usefully powered (or at least supported) by solar energy?

There are cars on the road that run on electricity instead of gasoline. And that's great, it really is. But you have to charge them, which is a problem if there are no charging stations in your area....
334 views

Many cells in parallel

If two or more cells of unequal voltages are connected in parallel (with the same terminal on the same side), is there a formula that gives the net potential difference? Also, by Kirchoff's loop law, ...
71 views

Why does all the voltage has to be dropped in a circuit?

In a simple circuit with a single resistor the entire voltage provided by the cell drops. It is independent of the resistance. Why does this happen? What is the mechanism behind this? I mean why does ...
181 views

How the current moves in the battery and outside the battery?

Does it move again to the negative terminal or stays at the positive terminal until the electrons all come .so the voltage will.be zero and current flow .I want simple clear explanation because i am ...
487 views

If two batteries that are fully charged with opposite polarities and one has higher emf.Does one will charge the other? [closed]

if there are two batteries fully charged in a circuit connected in series and one has higher emf than the other does one charge the other or not ? does any current pass in the circuit ?and if yes ...
165 views

Quartz piezoelectric battery

I'm designing a battery that uses quartz crystals to hold/produce a current for a long time using piezoelectricity. My question is: Would it be more efficient to have multiple small quartz crystals ...
152 views

What do the batteries actually do to the electrons?

I am plagued by this simple question that what force exactly causes the motion of an electron in the middle of a lattice of electrons of a wire? a. Is it an electric field created inside a wire due to ...
2k views

Connecting cells in series and parallel

When 2 cells is connected in series of the same emf like the following: [just the part of the circuit that I need...] The resultant emf will be twice as the previous identical emf. If we reverse ...
55 views

Is this Thevinin equivalent of a voltage divider, correct?

Found the PDF version of The Art of Electronics (Horowitz and Hill) recently, and, having nothing better to do... I thought I'd give it a read. It wasn't long before I hit a wall (courtesy: my inept ...
442 views

Why does battery generate less terminal voltage difference when current flows?

The terminal voltage difference of a battery means the difference of voltage between the two termials of a battery. Now, a battery has a voltage at the positive terminal and a voltage at the negative ...
2k views

676 views

Circuit with three capacitors and a switch [closed]

I have a homework problem where I have a battery connected to a capacitor and a switch that connects the capacitor to 2 others in series/disconnects the circuit from the battery. The question is: ...
572 views

Why is the voltage in my battery rising?

While playing with some 9 volt batteries in a series circuit, I noticed that the voltage of the battery as measured by my voltmeter was increasing at a constant rate. After placing a bulb in my ...
88 views

Current in circuits and conductivity

I'm really puzzled with a problem for a rather long time and I can't really seem to be able to solve it at all. It has to do with the electrons that move in a circuit. We know that a battery builds ...
1k views

What would the reading be on this voltmeter? Suppose The battery is $5V$. Would the reading be $5V$? If you see it from the other way, the two ends of the voltmeter are connected by ideal wires; ...
16k views

short circuit an alkaline battery

i'm not doing anything related to physics, but i'm just curious : What really happen when i short circuit an alkaline battery ? some article in the net shown that fire/explosion can be happened when ...
448 views

Does a higher e.m.f give a larger current?

I was told that e.m.f. is the work done on the charge carriers (i.e. electrons in wires or free ions in electrolytes). Does this mean that e.m.f is preportional to current (the rate of flow of charge)...
234 views

If a resistance of $0$ ohms and $x$ ohms are in parallel does all current pass through the $0$ resistance? [closed]

If a resistance of $0 \Omega$ and $x$ (and $x>0$) are in parallel does all current pass through the $0$ resistance? For instance in the following circuit: Set variable resistor to o ...