When Zhang Chi was doing the experiment of "changing the brightness of the lamp with a rheostat", she connected a small bulb in series with the sliding rheostat and the switch to the power supply, but after closing the switch, no matter how she moved the slide of the sliding rheostat, the light did not come on. In order to check the circuit fault, she took another voltmeter and connected the meter in parallel with the small bulb and the switch, the pointer of the meter did not move When it is connected in parallel with the sliding rheostat, the pointer of the meter is obviously deflected A. The power supply is dead B. open circuit at the small bulb C. open circuit at the sliding rheostat D. open circuit at the switch

When Zhang Chi was doing the experiment of "changing the brightness of the lamp with a rheostat", she connected a small bulb in series with the sliding rheostat and the switch to the power supply, but after closing the switch, no matter how she moved the slide of the sliding rheostat, the light did not come on. In order to check the circuit fault, she took another voltmeter and connected the meter in parallel with the small bulb and the switch, the pointer of the meter did not move When it is connected in parallel with the sliding rheostat, the pointer of the meter is obviously deflected A. The power supply is dead B. open circuit at the small bulb C. open circuit at the sliding rheostat D. open circuit at the switch

After closing the switch, no matter how to move the slide of the sliding rheostat, the light does not light up, indicating that there is an open circuit. When the voltmeter is connected in parallel with the sliding rheostat, the voltmeter shows the number, indicating that there is an open circuit at the sliding rheostat

How to judge the problem of physical circuit fault?
For the beginning of the circuit part of physics, I learned very well, but later I can't judge the circuit fault
I only know that there is a short circuit and an open circuit, but I can't tell at all. How can I judge? After determining the paragraph or short circuit, how can I judge whether there is something wrong with the electrical appliance or something?

This question is a bit too wide. When it comes to specific electrical appliances, it is more complicated. We can only say the way to judge short circuit and open circuit: short circuit: that is, there is no resistance added between two potentials (relatively high potential), which leads to the power supply electrode being directly connected by the conductor. What kind of voltage is involved

In the experiment, a student adjusted the slip rheostat after closing the switch. It was found that the number of voltage decreased, the bulb became brighter, the number of voltage increased and the bulb dimmed. (voltmeter connected in parallel at both ends of sliding rheostat)

Only when the bulb is connected in series with the sliding rheostat and the voltmeter is connected in parallel at both ends of the sliding rheostat, can it appear. When the sliding rheostat is connected, the current in the circuit increases, and the bulb becomes bright. At this time, the total voltage remains unchanged, and the voltage at both ends of the sliding rheostat decreases. Similarly, when the sliding rheostat is connected, the current in the circuit decreases, and the bulb becomes dark, and the voltage indicates that The bulb is connected in series with the sliding rheostat, and the voltmeter is connected in parallel at both ends of the sliding rheostat