page_title: Current divider
section_title: Example: RC combination
hierarchical_section_title: Current divider / Using Admittance / Example: RC combination
caption_attribution_description: Lowpass RC filter
context_page_description: In electronics, a current divider is a simple linear circuit that produces an output current (IX) that is a fraction of its input current. Current division refers to the splitting of current between the branches of the divider. The currents in the various branches of such a circuit will always divide in such a way as to minimize the total energy expended.
  The formula describing a current divider is similar in form to that for the voltage divider. However, the ratio describing current division places the impedance of the considered branches in the denominator, unlike voltage division where the considered impedance is in the numerator. This is because in current dividers, total energy expended is minimized, resulting in currents that go through paths of least impedance, hence the inverse relationship with impedance. Comparatively, voltage divider is used to satisfy Kirchhoff's Voltage Law. The voltage around a loop must sum up to zero, so the voltage drops must be divided evenly in a direct relationship with the impedance.
context_section_description: Figure 2 shows a simple current divider made up of a capacitor and a resistor. Using the formula below, the current in the resistor is given by:
  where ZC = 1/(jωC)  is the impedance of the capacitor and j is the imaginary unit.
  The product τ = CR is known as the time constant of the circuit, and the frequency for which ωCR = 1 is called the corner frequency of the circuit. Because the capacitor has zero impedance at high frequencies and infinite impedance at low frequencies, the current in the resistor remains at its DC value IT for frequencies up to the corner frequency, whereupon it drops toward zero for higher frequencies as the capacitor effectively short-circuits the resistor. In other words, the current divider is a low pass filter for current in the resistor.
caption: Figure 2: A low pass RC current divider
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