For example, in the case of a circuit using a constant voltage IC such as 78xx, which is easily available on the market, the overcurrent protection circuit operates within approximately 2A, so even if the output is shorted, there is no problem. Even if there is a short circuit, the IC is not damaged, and if the short circuit disappears, it operates again.
In most cases, a protection circuit is placed in case of a short circuit.
1. In case of not flowing more than a certain current (constant current)
2. When overcurrent is detected, the output is cut off and the power is turned OFF and ON again to restore the original state.
3. A cheaper way is to use a poly switch. The poly switch behaves like a permanent fuse that cuts off current due to its own heat when overcurrent flows, and returns to normal when cooled.
In the case of the ideal voltage source learned from the book, it maintains its own output voltage while flowing infinite current. But, it's literally Ideal and it's an imaginary object.
If the output of the constant voltage circuit or power supply used in real life is short, the following symptoms occur.
For example, in the case of a power supply with a rating of 24V 3A (72W), it maintains 24V until it supplies 3A of current, but when the current exceeds the rating, that is, 3A or more, the voltage starts to drop.
In other words, it squeezes its own force to supply the infinite current required by the short circuit, but it cannot exceed the rating, so the voltage lowers as the current above the rating is output.
When this happens, one of the following occurs:
1. The circuit that composes a short circuit, in this case it is mostly wires, but the circuit is broken by heat,
2. If the short circuit wire is strong enough, some of the internal parts of the power supply will be damaged.
3. In any case of 1 to 2, if a current higher than the rated current is passed, high heat may occur and a fire may occur.
4. Occasionally, in the case of a product with a built-in protection circuit, if a current exceeding the rating flows, the output stops and does not operate. In this case, remove the external short circuit and turn on the power again to operate normally.
<Answer 2>
It depends on the constant voltage circuit.
For example, in the case of a circuit using a constant voltage IC such as 78xx, which is easily available on the market, the overcurrent protection circuit operates within approximately 2A, so even if the output is shorted, there is no problem. Even if there is a short circuit, the IC is not damaged, and if the short circuit disappears, it operates again.
In most cases, a protection circuit is placed in case of a short circuit.
1. In case of not flowing more than a certain current (constant current)
2. When overcurrent is detected, the output is cut off and the power is turned OFF and ON again to restore the original state.
3. A cheaper way is to use a poly switch. The poly switch behaves like a permanent fuse that cuts off current due to its own heat when overcurrent flows, and returns to normal when cooled.
<Answer 1.>
In the case of the ideal voltage source learned from the book, it maintains its own output voltage while flowing infinite current. But, it's literally Ideal and it's an imaginary object.
If the output of the constant voltage circuit or power supply used in real life is short, the following symptoms occur.
For example, in the case of a power supply with a rating of 24V 3A (72W), it maintains 24V until it supplies 3A of current, but when the current exceeds the rating, that is, 3A or more, the voltage starts to drop.
In other words, it squeezes its own force to supply the infinite current required by the short circuit, but it cannot exceed the rating, so the voltage lowers as the current above the rating is output.
When this happens, one of the following occurs:
1. The circuit that composes a short circuit, in this case it is mostly wires, but the circuit is broken by heat,
2. If the short circuit wire is strong enough, some of the internal parts of the power supply will be damaged.
3. In any case of 1 to 2, if a current higher than the rated current is passed, high heat may occur and a fire may occur.
4. Occasionally, in the case of a product with a built-in protection circuit, if a current exceeding the rating flows, the output stops and does not operate. In this case, remove the external short circuit and turn on the power again to operate normally.