In sliding rheostat, AC, BC, BD and ad move R (resistance) and I (current) in P direction?

In sliding rheostat, AC, BC, BD and ad move R (resistance) and I (current) in P direction?

The key is to see the terminals clearly. If the top two terminals are connected, the sliding rheostat is equivalent to the wire. If the bottom two terminals are connected, the sliding rheostat is all connected to the circuit. If it is one up and one down, the direction of the current can be determined

There is a sliding rheostat in the series circuit, and there is a custom-made resistor. How does the moving slide P change the current

When the slide of sliding resistance is moved to make the resistance smaller, the current in series circuit will increase, otherwise it will decrease

If the sliding rheostat is connected in parallel with the resistor, and the slide P moves, does the current representation in series with the resistor change? Voltage type?

Normal answer: because the indication of the ammeter only represents the current in the circuit in series with the ammeter, and the sliding rheostat is in another branch, its resistance change will not affect the indication of the ammeter
When the resistance value of the sliding rheostat is zero, it is equivalent to a short circuit (short circuit) of the branch of the ammeter whose resistance is in series. Because the voltage is zero after being short circuited, the current is also zero, so the current indication will change and the indication will be zero
(therefore, when we design the circuit, we consider that the sliding rheostat has the problem of short circuit with its parallel circuit. We often use a fixed resistor in series with the sliding rheostat.)

Whether the resistance of a small bulb in a series circuit is accurate by "voltammetry" (a sliding rheostat is connected in series in the circuit)
Why move the sliding rheostat to measure three groups of different current and voltage data, and then use Ohm's law to measure the resistance, the resistance will be different. Isn't the resistance the nature of the conductor? How can it change?

The reason why the resistance changes is that the higher the temperature is, the higher the resistance is. Moreover, it should be noted that the resistance has nothing to do with voltage and current. In addition, when measuring, the data of voltage should be taken first, and then the sliding rheostat should be used to adjust to the voltage data, and the data of current can be obtained, and then the resistance can be calculated by Ohm's law