The power delivered to a load depends on the current flowing through it and the voltage drop across it. The current through the load at a constant voltage, in turn, depends on its resistance. It is possible to increase the power allocated to the load using both the first and the second of these regularities.
Instructions
Step 1
The first way to increase the power delivered to the load is to increase the voltage applied to it. Note that when the voltage increases n times, the current through the load will also increase n times, which means that the power will increase n ^ 2 times. This pattern is valid only if the resistance is unchanged. For real loads, with increasing voltage, the resistance can both fall and increase (the second case is more common). Accordingly, the dependence of power on voltage in this case turns out to be more complex than a simple quadratic.
Step 2
The second way to increase the power dissipation is to reduce the load resistance. For example, if this is a rheostat, you can slightly move its movable contact so that a piece of wire of a slightly shorter length is included in the circuit. If the power supply has a low internal resistance, the change in the load supply voltage can be neglected. Thus, with a decrease in the load resistance, the current through it will increase linearly at a constant voltage, which means that the power will also increase linearly.
Step 3
Some power supplies have such a high internal resistance that you have to take that into account as well. The power of the load connected to such a source, with a decrease in its resistance, increases until the latter equals the internal resistance of the source. It is in this mode that it is maximum, and the load itself, which has such a resistance, is called matched. A further decrease in the load resistance leads to a decrease in the power released on it, but it forces the source itself to emit a significant amount of heat. In some conditions, this can lead to its failure.
Step 4
The temperature to which the load will heat up is determined not only by the power released on it, but also by its mass. Therefore, before you force it, be sure to find out if this will lead to dangerous overheating. It may be necessary to provide for heat dissipation by a radiator, blowing with a fan, or both of these measures together. Make sure there is good thermal contact between the load and the heatsink. Please note that some devices, such as semiconductor lasers, are not damaged by overheating, but by an increase in the density of the emitted light energy.
