Part 4

C

This device is two zener diodes connected back to back in series and is used to support voltage surges and transients.

a. Thyristor

b. Varactor

c. Thyrector

d. Phanatron

A

Refers to the number of degrees of an AC cycle during which the SCR is turned on.

a. Conduction angle

b. Firing delay angle

c. Induction angle

d. ON angle

D

A four-element solid state device that combines the characteristics of a both diodes and transistors.

a. Varactor

b. Zener diode

c. Tunnel diode

d. SCR

D

Electron tube equivalent to solid state SCR.

a. Triode

b. VTVM

c. CRT

d. Thyratron

A

Find the two stable operating conditions of an SCR.

a. Conducting and non-conducting

b. Oscillating and quiescent

c. NPN conduction and PNP conduction

d. Forward conducting and reverse conducting

C

How do you stop conduction during which SCR is also conducting?

a. Remove voltage gate

b. Increase cathode voltage

c. Interrupt anode current

d. Reduce gate current

A

When an SCR is triggered or on conducting, its electrical characteristics are similar to what other solid-state device (as measured between its cathode and anode)?

a. The junction diode

b. The varactor diode

c. The tunnel diode

d. The hotcarrier diode

C

Which of the following does not have a base terminal?

a. UJT

b. PNP

c. SCR

d. NPN

B

A series RC circuit that is connected in parallel with an SCR to eliminate false triggering.

a. Crowbar

b. Snubber

c. Varistor

d. Eliminator

A

A circuit that protects a sensitive circuit from a sudden increase in supply voltage.

a. Crowbar

b. Snubber

c. Varistor

d. Eliminator

A

A two-terminal, bidirectional thyristor.

a. DIAC

b. Shockley

c. TRIAC

d. Diode

A

A DIAC is equivalent to inverse parallel combination of

a. Shockley diodes

b. Schottky

c. BJT

d. SCR’s

D

A TRIAC is equivalent to inverse parallel combination of

a. Shockley

b. Schottky

c. BJT

d. SCR’s

A

Which are the three terminals of a TRIAC?

a. Gate, anode1 and anode2

b. Gate, source and sink

c. Base, emitter and collector

d. Emitter, base1 and base2

D

Which device can be modeled by a diode and two resistors?

a. BJT

b. DIAC

c. SCR

d. UJT

D

The minimum emitter to base 1 voltage to trigger the UJT.

a. Forward breakover voltage

b. Trigger

c. Breakdown voltage

d. Peak voltage

D

The ratio of the emitter to base1 resistance to the interbase resistance of a UJT.

a. Aspect ratio

b. Current gain

c. Voltage gain

d. Intrinsic standoff ratio

B

For UJT, it is the region between the peak and valley points.

a. Active region

b. Negative resistance region

c. Trigger region

d. Saturation region

C

Typical breakover voltage of an SBS.

a. 2 V

b. 4 V

c. 8 V

d. 16 V

B

The trigger current is applied to the…

a. Anode

b. Gate

c. Cathode

d. Base

C

The region where breakover voltage of the SBS drops to 1 V instantaneously.

a. Falldown region

b. Fallback region

c. Breakback region

d. Breakdown region

A

The ratio of RB1 and RBB is called

a. Intrinsic standoff ratio

b. Reuber’s ratio

c. Common mode rejection ratio

d. Cat’s ratio

A

he time between the first application of electrode force and the first application of welding current.

a. Squeeze time

b. Weld time

c. Hold time

d. Off period

B

Process wherein coalescence is produced by the heat obtained from the resistance of the workpiece to the flow of low voltage, high density electric current in a circuit.

a. Forge welding

b. Resistance welding

c. Ultrasonic welding

d. LBW

B

Time when electrode force is applied but the current is shut off.

a. Off period

b. Hold time

c. Squeeze time

d. Weld time

C

The time when electrode force is released.

a. Hold time

b. Squeeze time

c. Off period

d. Weld time

D

The fusion of the grain structure of materials.

a. Forge

b. Weld

c. Recombination

d. Coalescence

A

Time when current is applied to the workpiece.

a. Weld time

b. Squeeze time

c. Hold time

d. Off period

D

Heat in resistance welding is produced by the following factors except one

a. Time duration

b. Current

c. Electrical resistance

d. Pressure applied

C

Resistance welding machine component that holds the workpieces.

a. Electrical circuit

b. Electrode system

c. Mechanical system

d. None of the above

C

Resistance spot welding (RSW) machine type that is controlled by hydraulic cylinders.

a. Miniature welders

b. Rocker-arm welder

c. Press-type welder

d. Portable spot welder

B

Machine component made up of the transformer and the current regulator.

a. Control system

b. Electrical system

c. Electrode system

d. Mechanical system

C

Welder machine with capacities up to 500 kVa

a. Miniature welders

b. Rocker-arm welder

c. Press-type welder

d. Portable spot welder

C

Regulates the time of the welding cycle.

a. Electrode

b. Current regulator

c. Control system

d. Mechanical system

D

Welding machine use for large workpieces.

a. Miniature welders

b. Rocker-arm welder

c. Press-type welder

d. Portable spot welder

D

Another name for hammer welding

a. Fusion welding

b. RW

c. Maul welding

d. Forge welding

A

Referred to as a localized coalescence

a. Weld

b. Mold

c. Cast

d. Metal

C

Part of the welding electric circuit that is used to produce high amperage current at low voltages.

a. Capacitor

b. Voltage regulator

c. Transformer

d. The secondary circuit

A

The overlapped RSW.

a. RSEW (Resistance Seam Welding)

b. ORSW

c. OSW

d. USW

B

pot welding are most commonly used in

a. Ships

b. Automobiles

c. Airplanes

d. Rafts

A

The last step in welding time control.

a. Off period

b. Weld time

c. Squeeze time

d. Hold time

B

The relative maximum workpiece thickness where spot welding can be used.

a. 0.5 in

b. 1 in.

c. 1.5 in.

d. 0.25 in.

D

Resistance welding was developed by this man in and revolutionized the welding industry.

a. Isaac Asimov

b. Karel Capek

c. Thomas Seebeck

d. Elihu Thomson

C

The year when resistance welding was discovered.

a. 1935

b. 1798

c. 1886

d. 1945

C

It is the fusion or growing of the materials being together.

a. Coalition

b. Coincidence

c. Coalescense

d. Mixing

A

Arc welding requires a voltage around _________.

a. 60 – 100 V

b. 150 -200 V

c. 400 – 440 V

d. 1000 – 5000 V

C

During arc welding, the current is in the range of _________.

a. 1 – 5 A

b. 5 – 50 A

c. 50 – 400 A

d. 500 – 4000 A

B

The body structure of the car is welded by _________.

a. Gas welding

b. Spot welding

c. Induction welding

d. Arc welding

A

For inspection of welding defects in thick metals, which of the following ray is used to photograph thick metals objects?

a. Gamma rays

b. Cosmic rays

c. Infrared rays

d. Ultraviolet rays

C

The voltage across an SCR when it is turned on is about

a. 0.5 V

b. 0.1 V

c. 1 V

d. 5 V