Resistance is short for resistance. What the questioner said is that the resistance is large, which can be understood as two kinds: the resistance value of the resistance is large and the volume of the resistance is large.
There are many kinds of resistors, such as carbon film resistance, metal film resistance, metal oxide film resistance, glass resistance, synthetic carbon film resistance, winding resistance, patch resistance and so on.
There is no direct relationship between resistance value and power. For example, carbon film resistance belongs to thin film resistance. It is formed by depositing resistance film on carbon film substrates. The thickness of this resistance film is less than several microns. Therefore, it is impossible to make a large power for this type of carbon film resistance. Generally, it can achieve 1/16W, 1/8W, 1/4W, 1/2W, 1W and 2W. But their resistance range can be very wide from 0.5_to 106_.
The resistance range of metal film resistance is larger than that of carbon film resistance (10 x 107_); the resistance range of metal oxide film resistance is larger, and the general resistance value is less than 200 k_; and the resistance range of synthetic film can be from 10_to 106 M.
To achieve high power, winding resistance or cement resistance is required.
The winding resistance of the circuit is made by winding steel wire or stranded alloy wire on the casing body and coating the outer layer with glass fiber or glass fiber protective layer. The maximum power of the winding resistance can reach 200W.
2. These resistors are classified into RX27-1, RX27-1V, RX27-3 (A, B, C), RX27-4 and so on. Among them, the power range of RX27-1 is 2-15W, the resistance range is 0.1-2200; and the power range of RX27-3 is 5555.5-3 (a, A, B, C), RX27-4, etc. ~ The resistance ranges from 0.1 to 2700_at 15W, the power range of RX27-4 is from 10 to 40W and the resistance range is from 0.1 to 4300_.
Simply from the volume of resistance, the larger the volume, the larger the power will be. Because resistance emits a lot of heat and consumes power when it has current, resistance manufacturers calculate it based on its rated resistance and power. Of course, it can cause resistance scalding, scorching and even scorching.
In view of the above, the concepts of heat resistance power, rated power and rated power of resistance are introduced. Heat-resistant power refers to the amount of heat dissipation that resistance can withstand per unit time, in terms of watt (W). Usually, the heat dissipation of resistance is related to the heat dissipation condition. The larger the volume of resistance, the easier the heat dissipation, so the larger the volume of the same kind of resistance. The higher the heat-resistant power is. Rated power refers to the maximum power allowed to be consumed by a resistor when it works for a long time, and its calculation formula is: P = I * u p = I2 * r p = U2 / R is the rated power of the resistor, unit w; I is the current flowing through the resistor, unit ampere (a); u is the voltage at both ends of the resistor, unit v; R is the resistance value of the resistor, unit_.