Jännitteenjakopiiri

Jännitteenjakopiiri, also known as a voltage divider, is a simple passive linear circuit that produces an output voltage (Vout) that is a fraction of its input voltage (Vin). It is typically constructed using two resistors connected in series. The input voltage is applied across the series combination of the two resistors, and the output voltage is taken across one of the resistors.

The fundamental principle behind a voltage divider is Ohm's Law and Kirchhoff's Voltage Law. When resistors R1 and R2 are connected in series across an input voltage Vin, the total resistance of the circuit is R1 + R2. The current flowing through the circuit is given by I = Vin / (R1 + R2). The voltage drop across R2, which is Vout, can then be calculated as Vout = I * R2. Substituting the expression for current, we get the voltage divider formula: Vout = Vin * (R2 / (R1 + R2)).

Voltage dividers are widely used in electronics for various purposes. They are commonly employed to reduce a high voltage to a lower one, providing a specific voltage level required by another component. They can also be used to create reference voltages, measure unknown resistances (when one of the resistors is replaced by a sensor whose resistance changes), or as a simple method for attenuating a signal.

However, voltage dividers have limitations. They are not efficient for power delivery because a significant amount of power is dissipated as heat in the resistors. Additionally, the output voltage of a voltage divider is sensitive to the load connected to its output. If a load draws current from the output, it effectively changes the resistance in parallel with R2, altering the output voltage. For applications requiring a stable voltage output that is independent of the load, a voltage regulator is a more suitable solution.