jännitteenjakopiirissä

A jännitteenjakopiiri, or voltage divider in English, is a simple electronic circuit that produces an output voltage that is a fraction of its input voltage. It is typically constructed using two or more resistors connected in series. The input voltage is applied across the entire series combination, and the output voltage is taken across one of the resistors.

The principle behind a voltage divider relies on Ohm's law and the properties of series circuits. In a series circuit, the current is the same through all components. The voltage across each resistor is proportional to its resistance. Therefore, by choosing appropriate resistor values, a specific fraction of the input voltage can be obtained as the output.

The formula for a simple two-resistor voltage divider is Vout = Vin * (R2 / (R1 + R2)), where Vout is the output voltage, Vin is the input voltage, R1 is the resistor between the input voltage and the output, and R2 is the resistor between the output and ground. This circuit is widely used for scaling voltages, providing reference voltages, and in sensor applications where a change in resistance needs to be converted into a change in voltage.

While simple and useful, voltage dividers have limitations. They are not efficient for powering significant loads, as the current drawn by the load will affect the output voltage. Additionally, the output voltage is only stable if the input voltage is stable and the resistances are precisely controlled. For applications requiring stable voltages under varying loads, voltage regulators are a more appropriate solution.