Under what circumstances are relay coils connected in parallel with resistors and capacitors

Under what circumstances are relay coils connected in parallel with resistors and capacitors

At the moment of Q2 opening, the relay is pulled in by capacitor C6, then C6 is gradually charged, and the current flowing through the relay is gradually reduced, but the resistance R5 can ensure that the relay current is not less than the release current. The function of RC in series with the relay coil is to make use of the difference between the relay pull-in current and the release current, so as to ensure that the relay is immediately pulled in when Q2 is opened, At the same time, the current flowing through Q2 is reduced during closing

Why is the thinner the conductor, the greater the resistance

The resistance of a conductor is related not only to the material of the conductor, but also to the cross-sectional area of the conductor. The formation of the current is the result of the movement of electrons. When the cross-sectional area is large, more electrons pass through in unit time and the resistance is small. On the contrary, the resistance is large
When the conductor is electrified, it is the same with the water pipe. If the water pipe is thin, the resistance will be large

The higher the temperature of those conductors, the greater the resistance; the lower the temperature of those conductors, the greater the resistance
Please give no less than 7 examples

The higher the temperature, the greater the resistance
One of the reasons why the temperature decreases is that the red glass is not suitable. The glass at normal temperature is insulator

Does the resistance of all metal conductors increase with the increase of temperature
Can you be more specific
Which metals are reduced?

No, it's also lower
Metal conduction is electron conduction. Electrons drift directionally under the action of electric field to form current in metal. When electrons move directionally in metal conductor, the smaller the obstruction, the smaller the resistance of conductor. On the contrary, the greater the obstruction, the less free they move and the greater the resistance of conductor
In the metal conductor, although the atomic realms in the crystal lattice basically keep regular arrangement, they are not static. Each atomic realms keep thermal vibration near its regular position, The thermal vibration of atoms in the whole conductor does not have a unified pace. In this way, the regularity of the arrangement of atoms is destroyed to a certain extent, and the obstruction to the movement of electrons is formed. The farther the thermal vibration of atoms is away from its regular position, the more chances of collision with electrons, the greater the obstruction to the drift of electrons, and the greater the resistance of the conductor
To sum up, the answer to the question is not hard to come out, because when the temperature rises, the thermal vibration of the atomic real increases, and the amplitude of the vibration increases. As a result, the chances of colliding with the atomic real and the times of colliding increase, so the resistance of the metal conductor increases, The relationship between resistance and temperature is
R ＝ R 0 ＋（ 1 ＋α t ）
Where R 0 is the resistance of the metal conductor at 0 ℃ and α is the temperature coefficient of resistance of the metal conductor. The temperature coefficient of resistance α of different metal materials is also different
But the resistance of some alloys changes little with temperature