Questions Without Answers For Power Supplies

Question File Number 21



Exam Page | Introduction | Control Panel | Booklist | Order Form | Questions | Study Notes

Amplifier | Mixer  | R Circuit | Resistors | Signals

Abbre  | Certificate | CW  | CW-Test  | Exam  | IARU  | ITU  | NZART  | Internet  | Syllabus

01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 | 11 | 12 | 13 | 14 | 15
16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30


  • A mains operated DC power supply:
    • converts DC from the mains into AC of the same voltage
    • converts energy from the mains into DC for operating electronic equipment
    • is a diode-capacitor device for measuring mains power
    • is a diode-choked device for measuring inductance power
    • ==========================
  • The following unit in a DC power supply performs a rectifying operation:
    • an electrolytic capacitor
    • a fuse
    • a crowbar
    • a full-wave diode bridge
    • ==========================
  • The following unit in a DC power supply performs a smoothing operation:
    • an electrolytic capacitor
    • a fuse
    • a crowbar
    • a full-wave diode bridge
    • ==========================
  • The following could power a solid-state 10 watt VHF transceiver:
    • a 12 volt car battery
    • 6 penlite cells in series
    • a 12 volt, 500 mA plug-pack
    • a 6 volt 10 Amp-hour Gel cell.
    • ==========================
  • A fullwave DC power supply operates from the New Zealand AC mains. The ripple frequency is:
    • 25 Hz
    • 50 Hz
    • 70 Hz
    • 100 Hz
    • ==========================
  • The capacitor value best suited for filtering the output of a 12 volt 1 amp DC power supply is:
    • 100 pF
    • 10 nF
    • 100 nF
    • 10,000 uF
    • ==========================
  • The following should always be included as a standard protection device in any power supply:
    • a saturating transformer
    • a fuse in the mains lead
    • a zener diode bridge limiter
    • a fuse in the filter capacitor negative lead
    • ==========================
  • A halfwave DC power supply operates from the New Zealand AC mains. The ripple frequency will be:
    • 25 Hz
    • 50 Hz
    • 70 Hz
    • 100 Hz
    • ==========================
  • The output voltage of a DC power supply decreases when current is drawn from it because:
    • drawing output current causes the input mains voltage to decrease
    • drawing output current causes the input mains frequency to decrease
    • all power supplies have some internal resistance
    • some power is reflected back into the mains
    • ==========================
  • Electrolytic capacitors are used in power supplies because:
    • they are tuned to operate at 50 Hz
    • they have very low losses compared to other types
    • they radiate less RF noise than other types
    • they can be obtained in larger values than other types
    • ==========================

tick 

Further details about NZART can be obtained from the web at  NZART. There are several categories of NZART membership which include Transmitting and Non-Transmitting. Anyone interested in radio can join. E-mail enquiries to  nzart@nzart.org.nz will bring details about NZART Membership. On-line details about  Joining NZART - Membership has advantages.
Contact Webmaster at e-mail  webmaster@nzart.org.nz
Compiled Sun Nov 28 2010 at 8:42:55pm


01 |  02 |  03 |  04 |  05 |  06 |  07 |  08 |  09 |  10 |  11 |  12 |  13 |  14 |  15
16 |  17 |  18 |  19 |  20 |  21 |  22 |  23 |  24 |  25 |  26 |  27 |  28 |  29 |  30

Introduction |  Control Panel |  Booklist |  Order Form |  Questions |  Study Notes