YILDIRIM BEYAZIT UNIVERSITY
ECE 204 - ELECTRICAL CIRCUITS II LABORATORY MANUAL – 5 – TRANSFER FUNCTIONS Materials: Below, minimum amount of components you will need to bring to laboratory is indicated. It is strongly recommended to have more components. No additional component will be given during experiments! Resistors: 3 x 10kΩ Capacitors: 3 x 10 nF Others: 1 x Breadboard, 20 x Jumper/Connection cables
Background: A two-port linear network can be in general described by a transfer function: H( jω ) = Vo ( ω ) / Vin ( ω); Given a sinusoidal input voltage Vi ( t )= Vm sin(ωo t ), the output voltage will be : Vo ( t )= │ H ( j ωo ) │ * sin (ωo t + Ө ( ωo )) ; Where │ H ( j ω ) │ and Ө ( ωo ) are, respectively, the magnitude and the phase equation of the transfer function at frequency ωo.
Laboratory Exercise: 1) Connect the circuits of figures 1.a and 1.b. R = 10kΩ and C = 10nF.
a. Experimentally find the input frequency where there is 45o phase difference in between input and output. 1.a: fi =
, 1.b: fi =
b. Experimentally find the input frequency where the output amplitude is ¼ of the input amplitude. 1.a: fi =
, 1.b: fi =
YILDIRIM BEYAZIT UNIVERSITY c. What is the maximum phase shift that can be achieved with these circuits? Are there any limitations in achieving this phase-shift? Make comments. _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ 2) Connect the circuits of figures 2 and 3.
For each circuit; a. Experimentally find the input frequencies where there is Âą90o phase difference in between input and output. What is output amplitude at these frequencies? 2.a: fi =
, 2.b: fi =
, 3: fi =
2.a: Vo =
, 2.b: Vo =
, 3: Vo =
b. Experimentally find the input frequencies where there is 0o or 180o phase difference in between input and output. What is output amplitude at these frequencies? 2.a: fi =
, 2.b: fi =
, 3: fi =
2.a: Vo =
, 2.b: Vo =
, 3: Vo =
c. What is the maximum phase shift that can be achieved with these circuits? Are there any limitations in achieving this phase-shift? Make comments. _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________
YILDIRIM BEYAZIT UNIVERSITY 3) Explain the effect of input frequency increment on the output signal amplitude and phase (for circuit in figure 3). Make comments. _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________