Why battery works only in DC and why it won’t work in AC? How AC is different from DC

So in order to know about the battery working in DC we must first know what is AC and what is DC current

A direct current is a current that is not varying while the AC signal is a sinusoidal wave it has a positive and negative wave so the AC current is a varying current. The AC current is a fluctuating current and DC is a nonfluctuating current and the DC current can be called a constant current. The AC current will change the direction periodically and because of this the voltage level also reverses with the current. Mostly AC is used to deliver power.

DC current can be described as the movement of the electron from the negative pole to the positive pole. The movement of the directional current will be a unidirectional flow. The source of the DC power is batteries, Electro-chemical, and photovoltaic cells. AC signal is a sinusoidal wave and it has a positive and negative half cycle. So the AC current that reaches our home is varying it would vary as the positive and negative cycles. The above image shows the AC cycle in which one positive and negative cycle is considered as a wave. There is the frequency in alternating current and it is the number of cycles per second, so the frequency is calculated according to the wave. So if we connect a bulb to an AC signal that has a frequency of 50 which would be per second then the bulb will be on and off fifty times and it is dependent on the frequency we won’t be able to see this because the process is too fast so we can only see the bulb glow.

What are the major difference between AC & DC?

The AC signal is fluctuating current and it has positive and negative cycles, while the DC is direct and its magnitude is not varying with time. The AC is varying with time. So there is no frequency in DC current, and the DC signal is unidirectional so the DC current doesn’t have a positive or negative cycle it gives constant current. Because of this, we won’t say positive and negative in AC we say phase and neutral because there is both positive and negative. In the phase, there are positive and negative, while in DC we say the negative and positive section because it is not varying. So the DC is unidirectional and it won’t vary with time and there is no frequency.

Why the battery works in DC and why not in AC?  What would happen if we connect a battery with AC?

A battery doesn’t store electrical energy directly it converts the electrical energy into chemical energy and then stores it. This chemical energy is then converted into electrical energy while the battery is used. This electrical energy that is used in the battery is DC and not AC. So a battery consist of a positive and negative charged electrode and this electrode will be immersed in an electrolyte which is a fluid. This electrolyte also has electrons and charge too. So when we connect a load to the electrodes then the circuit will be completed and the electrons will flow from the higher side to the lower side and this flow is the current, so the chemical reaction takes place according to the attraction and repulsion of the electrons and in this way the battery works. So if we connect an AC power to the battery, the ac terminals are connected to the battery’s electrodes and the positive cycle would charge the battery and the AC also has negative cycle which would discharge the battery so there won’t be any battery charging because the charging and discharging is in the same amount equal positive and negative half cycle, and the battery would be damaged and that’s why the battery only works in DC current.


post-graduate in Electronics & communication.

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