ASVAB Electronic Information #1

What are the three leads of a common transistor? a. Collector, Base, Emitter b. Base, Collector, Case c. Emitter, Collector, Bias d. Collector, Bias, Omiter

A; In a common transistor the common leads are the collector, base, and emitter.

The convenience outlet above that is known as a polarized outlet is number... a. 1 b. 2 c. 3 d. 4

A; The plug can go into the outlet in only one way in a polarized outlet. In the other outlets, the plug can be reversed.

In electronic circuits, the symbol shown above usually represents a... a. resistor. b. battery. c. capacitor. d. transformer.

B; A battery is an assembly of chemical cells. The common 9-volt battery found in transistor radios consists of six 1.5-volt cells connected in series to produce a total of six times 1.5 volts—or 9 volts.

Connecting a lead for the anode to the cathode of a battery will produce... a. a high-resistance circuit. b. a short circuit. c. a low current path. d. an open circuit.

B; Connecting a lead from the anode to the cathode of a battery produces a short circuit.

In a house bell circuit, the push button for ringing the bell is generally connected in the secondary of the transformer feeding the bell. One reason for doing this is to... a. save power. b. keep line voltage out of the push button circuit. c. prevent the bell from burning out. d. prevent arcing of the vibrator contact points in the bell.

B; Connecting the bell to a 6- or 12-volt source on the secondary of a transformer is done as a safety precaution. The other way would be dangerous.

What does LED stand for? a. Light Emitting Display b. Low Energy Display c. Light Emitting Diode d. Light Emitting Detector

C; LED stands for Light Emitting Diode.

Microfarads are units of measurement usually associated with... a. sockets. b. switches. c. capacitors. d. connectors.

C; The farad is a unit of capacitance. Most capacitors used in electronics are small and their capacitance is only a tiny fraction of a farad. One microfarad is one-millionth of a farad.

In comparing Nos. 00, 8, 12, and 6 A.W.G. wires, the smallest of the group is... a. No. 00 b. No. 8 c. No. 12 d. No. 6

C; The number on the wires is in reverse order to the amount of current that they can carry. No. 12 is the smallest of the wires.

A "centi" measures a(n)... a. eighth. b. millionth. c. hundredth. d. ten-thousandth.

C; The prefix centi refers to 100.

An electrician should consider all electrical equipment "live" unless he or she definitely knows otherwise. The main reason for this practice is to avoid... a. doing unnecessary work. b. energizing the wrong circuit. c. personal injury. d. de-energizing a live circuit.

C; This is a general safety question. Never assume that there is no current in a piece of electrical equipment; the results could be shocking.

Is it proper procedure to ground the frame of a portable motor? a. No. b. No, if it is AC. c. Yes, unless the tool is specifically designed for use without a ground. d. Yes, if the operation takes place only at less than 150 volts.

C; This is a proper safety procedure and should be followed.

To control a lamp from two different positions, it is necessary to use... a. two single-pole switches. b. one single-pole switch and one four-way switch. c. two three-way switches. d. one single-pole switch and two four-way switches.

C; Two three-way switches will control a lamp from two different positions.

If voltage is represented by V, current by I, and resistance by R, then the one of the following that correctly states Ohm's Law is... a. R = V × I b. R = I ⁄ V c. V= IR d. V = I ⁄ R

C; Using algebraic rules, Ohm's Law can be written in three equivalent ways: "R= V/I; I = V/R; V = IR

To determine directly whether finished wire installations possess resistance between conductors and ground, use... a. clamps. b. set screws. c. shields. d. a megger.

D; A megger (megohmmeter) is a portable device that produces a voltage. It is used to check for a high-voltage breakdown of insulation. In this case, it uses a resistance measurement to determine continuity.

The device used to change AC to DC is a... a. frequency changer. b. transformer. c. regulator. d. rectifier.

D; A rectifier is a device that changes AC to DC and often includes one or more diodes.

The device that is often used to change the voltage in alternating current circuits is the... a. contractor. b. converter. c. rectifier. d. transformer.

D; Converters change DC to AC. Rectifiers change AC to DC. Contactors are remote-controlled switches frequently used as part of elevator controls. Transformers change voltages in AC circuits in accordance with the ratio of the number of turns in the secondary winding to the number of turns in the primary winding.

The core of an electromagnet is usually... a. aluminum. b. brass. c. lead. d. iron.

D; Soft iron has the property of being easily magnetized or demagnetized. When the current is turned on in an electromagnet, it becomes magnetized. When the current is turned off, the iron loses its magnetism.

The sketch above shows a head-on view of a three-pronged plug used with portable electric power tools. Considering the danger of shock when using such tools, it is evident that the function of the U-shaped prong is to... a. ensure that the other two prongs enter the outlet with the proper polarity. b. provide a half-voltage connection when doing light work. c. prevent accidental pulling of the plug from the outlet. d. connect the metallic shell of the tool motor to the ground.

D; The third prong in the plug is the grounding wire..

Wires are often spliced by the use of a fitting like the one shown above. The use of this fitting does away with the need for... a. skinning. b. cleaning. c. twisting. d. soldering.

D; This is a mechanical or solderless connector. It does away with the need to solder wires and is found in house wiring.

The five lamps shown above are each rated at 120 volts, 60 watts. If all are good lamps, lamp 5 will be... a. much brighter than normal. b. about its normal brightness. c. much dimmer than normal. d. completely dark.

D; This is the Wheatstone bridge circuit with balanced loads in each of its arms. Because there is no voltage across lamp No. 5, it will not be lit.