The purpose of using a three wire power cord and plug on amateur equipment is to:
  1. make it inconvenient to use 2. prevent the plug from being reversed in the wall outlet 3. prevent the chassis from becoming live in case of an internal short to the chassis 4. prevent short circuits

Before checking a fault in a mains operated power supply unit, it would be safest to first:
1. short out the leads of the filter capacitor 2. turn off the power and remove the power plug 3. check action of the capacitor bleeder resistor 4. remove and check fuse from the power supply

An important part of a simple power supply is the diode
used in the rectifier. It can convert AC to DC since it:
1. has a high resisitance to AC but not to DC 2. has a high resistance to DC but not to AC 3. allows electrons to flow in only one direction from anode to cathode 4. allows electrons to flow in only one direction from cathode to anode

Filter capacitors are connected in series to:
1. withstand greater voltage input 2. increase capacity 3. reduce ripple voltage 4. resonate filter circuit

In an AC to DC power supply to operate a radio, three essential sections are:
1. transformer - rectifier - filter 2. transformer - resonant circuit - diode 3. rectifier - voltage divider - filter 4. voltage divider - diode rectifier - resonant circuit

In an AC to DC power supply, the component value that
most determines the final voltage of the supply is the:
1. filter capacitance 2. transformer 3. inductance of the choke 4. peak inverse ratings of the diodes

If the primary of a 100 volt power transformer consists of 1100 turns, then a secondary winding supplying filament power for a 5 volt filament tube drawing 0.3 amps would be:
1. 20 turns 2. 70 turns 3. 50 turns 4. 7 turns

A transformer has a 240 volt primary that draws a current of 250 mA from the mains supply. Assuming no losses, what current would be available from a 12 volt secondary:
1. 215 amperes 2. 5 amperes 3. 25 amperes 4. 50 amperes

A dry cell has an open circuit voltage of 1.5 volts. When supplying a
great deal of current, the voltage may drop to 1.2 volts. This is due to the cell's:
1. internal resistance 2. voltage capacity 3. electrolyte becoming dry 4. current capacity

The action of changing alternating current to direct current is called:
1. amplification 2. detection 3. rectification 4. sublimation