The 9V battery in the multimeter is measured to be 9.3V Why can't it be carried?
1. The instantaneous current of carbon battery is large, but it doesn't last long! The point is cheap! If you don't use it, leave it for a month or two and basically consume a lot of electricity. When you run out of electricity, change the spare battery, and find that it doesn't take long to run out of electricity. The specific performance is that the multimeter shows it and there is no word. Turn it off and on again to show it. Take off the measured voltage, which is 8V.
2. The alkaline battery has stable output and long service life, which is very suitable for multimeter. I used to use carbon batteries all the time, and I had to use several pieces a year. I haven't seen your fault since I changed the alkaline battery of a well-known domestic brand. Think about it, the voltage resistance is being tested. The multimeter is low in power and there is a big error. Cheat people? The low discharge capacity of alkaline batteries can make them last for a long time. With a quality guarantee of 10 years, you can keep it at ease.
Don't use 5 yuan carbon batteries in the future, use 10 yuan alkaline batteries. Our maintenance personnel, their own batteries, must be used well! Don't use cheap goods, it's true that you get what you pay for! I am deeply touched.
The voltage is just a potential difference, which only indicates that there is a potential difference between these two places. The existence of a potential difference does not mean that there must be a current. For example, when a battery is left empty, there is a potential difference between the two electrodes, but there is no current, because there is no conductor to form a loop.
What if there is a loop? One of the most extreme cases is to directly connect the two ends of the electrode with a wire (such as copper wire). It is supposed that there should be a great current at this time. After all, the resistance of the conductor (copper wire) is very small, and according to Ohm's law, the current is definitely not small. This is because the battery itself has a resistance as a power supply, and this resistance (internal resistance) is very large (relative to the wire), and the current that the battery can provide is also affected.
When the battery is used or left for a period of time, the internal resistance of the battery will increase, and the final result is that it can't draw much current. Although the voltage can be measured at no load at this time, when you connect a load to draw current, the voltage will drop rapidly due to the internal resistance, which eventually leads to the failure of the battery to supply power normally.
In order to solve this problem, some people used to inject salt water into the battery to reduce the internal resistance, which would restore the power supply capacity of the battery in a certain time. However, when the medicine or electrode reaction inside the battery runs out, it is useless to inject anything into the battery at this time.
If your 9V battery is used quickly, it is recommended that you use rechargeable batteries, that is, ordinary batteries, and also the freshest batteries. All batteries have factory dates, but some people will repackage old batteries or even used batteries with dates, so the place to buy batteries is also very important.
