Johtojännitteistä

Johtojännitteistä refers to voltage drops that occur within electrical conductors. When current flows through a wire, the conductor has a finite resistance, which, according to Ohm's Law (V=IR), results in a voltage drop across its length. This voltage drop is a consequence of the energy dissipated as heat due to the resistance of the material.

The magnitude of the johtojännitteistä depends on several factors, including the current flowing, the resistivity of the conductor material, the length of the conductor, and the cross-sectional area of the conductor. Materials with lower resistivity, such as copper and aluminum, will exhibit less voltage drop for the same current and dimensions compared to materials with higher resistivity. Similarly, thicker wires (larger cross-sectional area) and shorter lengths will experience smaller voltage drops.

In electrical systems, significant johtojännitteistä can be detrimental. It leads to a reduction in the voltage available at the load, potentially causing devices to malfunction or operate inefficiently. For instance, in long power distribution lines, a considerable voltage drop can occur between the power source and the consumers. This is why power companies often use high voltages for transmission to minimize current and thus voltage drop, and then step down the voltage closer to the end-users. In electronics, particularly in low-voltage applications, even small voltage drops in PCB traces or connector pins can be critical. Careful design considerations, including conductor sizing and material selection, are employed to mitigate unwanted voltage drops.