What voltage does a battery board not connect to the load actually refers to?

You mean the voltage at the end of the battery (mains) when the load (bulb) is disconnected. This refers to the voltage at both ends of the battery (power supply). It can also be said that the open circuit voltage or open circuit voltage of the battery.

What you say about 'not connected' should mean that the power supply does not pass through the load (bulb) to form a loop, the load has no current flowing, and the bulb does not light up, but it does not mean that the positive and negative poles of the power supply are directly connected with wires!

Not only do you not understand what the teacher said, but you also add branches and leaves, the voltage when the circuit is broken is that the positive and negative poles of the battery board are not connected to any other load except for the measuring instrument, and the load is not connected (open circuit) and not connected directly with a wire through the load (short circuit) are completely different things.

You may ask, the measuring instrument is also a load, how can it be said that it is an open circuit? Under normal circumstances, when we do not make precise measurements or the impedance of the circuit under test is not particularly large, the influence of the internal resistance of the instrument is negligible. In other words, what you're measuring now is basically the electromotive force of the panel.

Why does the question you ask look so messy?

Not connecting the load means that the resistance of your external circuit is infinite, and there is only one battery internal resistance left.

At this time, strictly speaking, the voltage cannot be measured.

You can measure the voltage.

This means that you have formed a current loop.

Don't tell me anything like the voltage at infinity resistance.

In practice, this kind of rhetoric is nonsense.

Open-circuit voltage, no-load voltage, just one battery, no wiring.

Refers to the open-circuit voltage of the power supply, i.e., the electromotive force of the power supply. Addendum: Can you simply think of it as the voltage of a dry cell battery that is not loaded?

As long as your UPS output is open and closed, there will be voltage.

The UPS is not connected to the load, and its output still has voltage.

Yes As long as the computer is turned on, there is an output.

The electromotive force of the battery is equal to the open-circuit voltage, so e=u=600 V;

The short-circuit current is i short = 30 a, according to Ohm's law of closed circuits, there is: i short = er to solve the internal resistance of the panel r = ei short.

600μv30μa

then the current flowing through the appliance i=e

r+r=600μv

20 A: The current flowing through the appliance is 20 A

Example: When the power supply is not connected to the load, there is no current output, and the voltage between the positive and negative poles of the power supply is called the open circuit voltage, which is equal to the electromotive force of the power supply and is the maximum value. After the load is connected, the power supply has a current output to the load, and there is a voltage loss on the internal resistance of the power supply, and the output voltage of the power supply will decrease, which is called the road-end voltage.

This question should be combined with the actual situation to figure out what is "open circuit voltage" and what is "short circuit current".

The open-circuit voltage is the road-end voltage when the external circuit is disconnected, which is numerically equal to the electromotive force of the power supply; The short-circuit current is the current when the external circuit is short-circuited, r=e i short=600 30=20 ohms.

a. The voltage of the battery plate when it is not connected to the load is 600 V, and the electromotive force of the battery board is 600 V, so A is correct;

b. From the question, e=u=, and e=i short r, get: r= 20 so b is correct;

c. If the resistance of a 20 is formed into a closed circuit with the panel, the current in the circuit: i er+r

The output power of the 2A power supply is: P=IR=Therefore, C is wrong;

d. The electromotive force of the power supply is determined by the power supply itself, and has nothing to do with the resistance value of the external circuit

This is its characteristic, which is determined by the material.

Just like an ordinary battery, the smallest unit in it is 2V. Any piece of solar cell, regardless of its size, has a certain voltage, generally is.

This is 12 volts, and it generally needs to be replaced after 3-5 years, and the life span is not long even after repair.