This is a model of the AC and transient signal behavior of an RC series circuit. The AC characteristics include the attenuation factors (ratio of AC output to input voltage) and phase shifts for both high-pass and low pass outputs. The variables Et, Eo, t, and Tr refer to the transient behavior of the low-pass output to a step input of zero to Eo volts at t=0.
Variable Sheet ______________________________________________________________________________ St Input Name Output Unit Comment Xc 10 KOhm capacitive reactance (Ohm, KOhm, MOhm) 60 f Hz frequency (Hz, KHz) C .26525824 µF capacitor value (F,µF) 10 R KOhm Resistor (Ohm, KOhm, MOhm) Z 14142.136 Ohm Impedance (Ohm, KOhm, MOhm) 60 fo Hz corner frequency (Hz, KHz) alphaL .70710678 Low-pass attenuation factor (unitless) alphaH .70710678 High-pass attenuation factor (unitless) ThetaL 45 degrees Low pass phase angle (radians, degrees) ThetaH 45 degrees High pass phase angle (radians, degrees) Tc .00265258 sec Time constant (sec, msec, µsec) Et .98994816 volts Voltage at time t (volts, mV,µV) 1 Eo volts Steady-state voltage (volts, mV,µV) .01220188 t sec time after step input (sec, msec, µsec) Tr .01220188 sec 1 % response time (sec, msec, µsec) Rule Sheet _________________________________________________________________________________ S Rule Xc=1/(2*Pi()*f*C) "Reactance of capacitor Z=SQRT((R*R)+(Xc*Xc)) "Impedance of series RC circuit fo=1/(2*Pi()*R*C) "Frequency at which alpha = 0.707 alphaL=Xc/Z "ratio of output to input ac voltage (low pass) alphaH=R/Z "ratio of output to input ac voltage (high pass) Tan(Pi()/2-ThetaL)=Xc/R "Low pass phase angle ThetaH=Pi()/2-ThetaL "High pass phase angle Tc=R*C "Time constant Et=Eo*(1-exp(-t/Tc)) "Transient response of RC circuit Tr=4.6*Tc "1 percent response time