How to find impendence in a series parallel circuit without using imaginary numbers. The circuit in question has a voltage source of 25 volts frequency is 100 Khz then the R1 resistor 220 ohms in series with an inductor and a resistor that are in parallel with each other. The inductor L1which is 1.0mH that is in parallel with another resistor R2 that is 1500 ohms.