This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Problems Section 4.1 4.1 Starting with the current-voltage characteristic for a capacitor C , show that for the case of full-wave rectification and RC filtering v ripple i Load 2 fC , where i Load is the load current and f is the frequency of the ac input. 4.2 Show that Eq. 4.12 cos = 1- v ripple v max applies to both half-wave and full-wave rectification. 4.3 The circuit of Fig. P4.3 features an ideal diode and 0.6-V output ripple. The ac power source ( V s ) produces 18 V rms at 200 Hz. (a) Determine the maximum instantaneous load current (through R ). (b) Determine the time duration of the intervals of forward diode bias. (c) Find the maximum instantaneous diode current. (d) Find the diode peak reverse voltage. v out R 500 C V s + + Figure P4.3 4.4 A particular circuit with RC filtering rectifies a 50-Hz voltage waveform. Two conditions are known: The capacitor value is 10 mF. The current to the parallel RC combination has the time dependence shown in Fig. P4.4. (a) Does the circuit feature half-wave or full-wave rectification? (b) Determine the ripple voltage. (c) Find the maximum instantaneous load current. i (A) 10 10 20 t (ms) 0.5 ms Figure P4.4 4.5 Design a capacitively filtered half-wave rectifier circuit to deliver 50 mA to a 400- load resistance with 2-% ripple voltage. Specify the diode ratings. Assume a 60-Hz 115-V (rms) power source. 4.6 Repeat Problem 4.5 with full-wave rectification. 4.7 Design a capacitively filtered half-wave rectifier circuit to deliver 100 mA to a 100- load resistance with 5-% ripple voltage. Specify the diode ratings. Assume a 60-Hz 115-V (rms) power source. 4.8 Repeat Problem 4.7 with full-wave rectification. 4.9 The 4.7-mF (electrolytic) capacitor selected for the RC-filtered power supply of Example 4.1 has a parasitic equivalent series resistance (ESR) of 75 m. Estimate the power dissipated in the capacitor when R L = 200 (minimum load resistance). c 2010 Edward W. Maby All Rights Reserved 4.10 This problem features a diode as a detector . In a simple amplitude modulation (AM) process, a received radio signal has the form v r ( t ) = v m (1 + m sin m t )sin c t , where c is the carrier angular frequency (to which the radio is tuned), m is the modulating angular frequency of the signal with information content, and constant m is the modulation index (0 m 1). In what follows, let c and m correspond to 10-kHz and 1-kHz frequencies, respectively. In practice, c is significantly larger, and m is part of a spectrum with particular v m weightings. (a) Use SPICE to plot v r ( t ) over two m periods. Assume that the signal is applied to a 1-k load, and let m = 1....
View Full Document
This note was uploaded on 09/26/2010 for the course BME 405L taught by Professor Maarek during the Fall '10 term at USC.
- Fall '10